SHOW THE WORK

The evidence
behind the explanation.

Primary sources, clear provenance, original artwork. Factual reliance is not a claim that a source's images are free to reuse.

How to read this register

Source dates belong to the original publication; “not stated” means we did not establish a publication date. Source records show their consultation dates: the original edition was checked on 13 November 2026, with connected-edition additions on 14 November 2026. Source prose is paraphrased, not republished. Links are provided for verification and further reading.

Download the full source and asset register (JSON) ↗

Electricity

eia-delivery

How electricity is delivered to consumers

U.S. Energy Information Administration · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: EIA states its government information products are public domain in the United States; third-party material and marks are excluded. No worldwide asset license is assumed.
Use in this guide: Factual reference for independently written explanations; no source prose, photographs, logos, or diagrams reproduced.
Attribution: U.S. Energy Information Administration, How electricity is delivered to consumers (Not stated).
Modifications: None to source material. Explanations and schematic drawings are original.

eia-glossary

Electricity glossary

U.S. Energy Information Administration · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: EIA states its government information products are public domain in the United States; third-party material and marks are excluded. No worldwide asset license is assumed.
Use in this guide: Factual reference for independently written explanations; no source prose, photographs, logos, or diagrams reproduced.
Attribution: U.S. Energy Information Administration, Electricity glossary (Not stated).
Modifications: None to source material. Explanations and schematic drawings are original.

doe-101

Electricity 101

U.S. Department of Energy · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No source text or assets reused; no license for third-party material or marks assumed.
Use in this guide: Factual reference for independently written explanations; no source prose, photographs, logos, or diagrams reproduced.
Attribution: U.S. Department of Energy, Electricity 101 (Not stated).
Modifications: None to source material. Explanations and schematic drawings are original.

eia-generation

How electricity is generated

U.S. Energy Information Administration · Source date: 2023-10-31 · Accessed: 2026-11-13

Rights / licence: EIA states its government information products are public domain in the United States; third-party material and marks are excluded. No worldwide asset license is assumed.
Use in this guide: Factual reference for independently written explanations; no source prose, photographs, logos, or diagrams reproduced.
Attribution: U.S. Energy Information Administration, How electricity is generated (2023-10-31).
Modifications: None to source material. Explanations and schematic drawings are original.

eia-measuring

Measuring electricity

U.S. Energy Information Administration · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: EIA states its government information products are public domain in the United States; third-party material and marks are excluded. No worldwide asset license is assumed.
Use in this guide: Factual reference for independently written explanations; no source prose, photographs, logos, or diagrams reproduced.
Attribution: U.S. Energy Information Administration, Measuring electricity (Not stated).
Modifications: None to source material. Explanations and schematic drawings are original.

eia-circuits

Batteries, circuits, and transformers

U.S. Energy Information Administration · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: EIA states its government information products are public domain in the United States; third-party material and marks are excluded. No worldwide asset license is assumed.
Use in this guide: Factual reference for independently written explanations; no source prose, photographs, logos, or diagrams reproduced.
Attribution: U.S. Energy Information Administration, Batteries, circuits, and transformers (Not stated).
Modifications: None to source material. Explanations and schematic drawings are original.

eia-storage

Energy storage for electricity generation

U.S. Energy Information Administration · Source date: 2023-08-28 · Accessed: 2026-11-13

Rights / licence: EIA states its government information products are public domain in the United States; third-party material and marks are excluded. No worldwide asset license is assumed.
Use in this guide: Factual reference for independently written explanations; no source prose, photographs, logos, or diagrams reproduced.
Attribution: U.S. Energy Information Administration, Energy storage for electricity generation (2023-08-28).
Modifications: None to source material. Explanations and schematic drawings are original.

eia-solar

Photovoltaics and electricity

U.S. Energy Information Administration · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: EIA states its government information products are public domain in the United States; third-party material and marks are excluded. No worldwide asset license is assumed.
Use in this guide: Factual reference for independently written explanations; no source prose, photographs, logos, or diagrams reproduced.
Attribution: U.S. Energy Information Administration, Photovoltaics and electricity (Not stated).
Modifications: None to source material. Explanations and schematic drawings are original.

epa-delivery

Electricity Delivery and its Environmental Impacts

U.S. Environmental Protection Agency · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No source text or assets reused; no license for third-party material or marks assumed.
Use in this guide: Factual reference for independently written explanations; no source prose, photographs, logos, or diagrams reproduced.
Attribution: U.S. Environmental Protection Agency, Electricity Delivery and its Environmental Impacts (Not stated).
Modifications: None to source material. Explanations and schematic drawings are original.

aemo-fcas

Guide to Frequency Control Ancillary Services

Australian Energy Market Operator · Source date: 2025-09-17 · Accessed: 2026-11-13

Rights / licence: Copyright AEMO. Used only as a cited factual reference; no text, tables, or diagrams reproduced.
Use in this guide: Factual reference for independently written explanations; no source prose, photographs, logos, or diagrams reproduced.
Attribution: Australian Energy Market Operator, Guide to Frequency Control Ancillary Services (2025-09-17).
Modifications: None to source material. Explanations and schematic drawings are original.

eia-rights

Copyrights and Reuse

U.S. Energy Information Administration · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: EIA states its government information products are public domain in the United States; third-party material and marks are excluded. No worldwide asset license is assumed.
Use in this guide: Factual reference for independently written explanations; no source prose, photographs, logos, or diagrams reproduced.
Attribution: U.S. Energy Information Administration, Copyrights and Reuse (Not stated).
Modifications: None to source material. Explanations and schematic drawings are original.

doe-inverters

Solar Integration: Inverters and Grid Services Basics

U.S. Department of Energy · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No source prose, photographs, or diagrams reused; third-party assets and marks are not assumed reusable.
Use in this guide: Factual support for original explanations of inverters, backup operation, and distributed generation.
Attribution: U.S. Department of Energy, Solar Integration: Inverters and Grid Services Basics (date not stated).
Modifications: None to source material. All prose and drawings are original.

doe-distributed

Solar Integration: Distributed Energy Resources and Microgrids Basics

U.S. Department of Energy · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No source prose, photographs, or diagrams reused; third-party assets and marks are not assumed reusable.
Use in this guide: Factual support for original explanations of inverters, backup operation, and distributed generation.
Attribution: U.S. Department of Energy, Solar Integration: Distributed Energy Resources and Microgrids Basics (date not stated).
Modifications: None to source material. All prose and drawings are original.

neso-inertia

What is inertia?

National Energy System Operator (Great Britain) · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only; copyright remains with the named institution. No source prose, photographs, diagrams, or marks reproduced.
Use in this guide: Primary factual reference for independently written educational explanations and clearly labelled illustrative examples.
Attribution: National Energy System Operator (Great Britain), What is inertia? (Not stated).
Modifications: None to source material. All explanations and teaching examples are original.

cpuc-demand-response

Demand Response (DR)

California Public Utilities Commission · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only; copyright remains with the named institution. No source prose, photographs, diagrams, or marks reproduced.
Use in this guide: Primary factual reference for independently written educational explanations and clearly labelled illustrative examples.
Attribution: California Public Utilities Commission, Demand Response (DR) (Not stated).
Modifications: None to source material. All explanations and teaching examples are original.

Water

water-cdc-treatment

How Water Treatment Works

US Centers for Disease Control and Prevention · Source date: 2026-11-10 · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: US Centers for Disease Control and Prevention — How Water Treatment Works
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-who-safety

Water safety planning

World Health Organization · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: World Health Organization — Water safety planning
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-epa-source

Basic Information about Source Water Protection

US Environmental Protection Agency · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: US Environmental Protection Agency — Basic Information about Source Water Protection
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-usgs-groundwater

Groundwater Flow and the Water Cycle

US Geological Survey, Water Science School · Source date: 2026-09-17 · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: US Geological Survey, Water Science School — Groundwater Flow and the Water Cycle
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-nhmrc-coagulation

8.3.2 Coagulation and flocculation

Australian National Health and Medical Research Council · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: Australian National Health and Medical Research Council — 8.3.2 Coagulation and flocculation
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-oregon-treatment

Surface Water Treatment: Optimization, Training and Other Resources

Oregon Health Authority · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: Oregon Health Authority — Surface Water Treatment: Optimization, Training and Other Resources
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-seqwater-treatment

Water treatment

Seqwater · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: Seqwater — Water treatment
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-epa-technologies

Overview of Drinking Water Treatment Technologies

US Environmental Protection Agency · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: US Environmental Protection Agency — Overview of Drinking Water Treatment Technologies
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-epa-residuals

Drinking Water Treatment Plant Residuals Management: Technical Report

US Environmental Protection Agency · Source date: 2011-09 · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: US Environmental Protection Agency — Drinking Water Treatment Plant Residuals Management: Technical Report
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-cdc-disinfection

About Water Disinfection with Chlorine and Chloramine

US Centers for Disease Control and Prevention · Source date: 2026-11-10 · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: US Centers for Disease Control and Prevention — About Water Disinfection with Chlorine and Chloramine
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-wa-disinfection

Drinking Water Disinfection

Washington State Department of Health · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: Washington State Department of Health — Drinking Water Disinfection
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-sydney-pressure

Water Pressure Management Program

Sydney Water · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: Sydney Water — Water Pressure Management Program
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-sydney-planning

Water System Planning Guideline

Sydney Water · Source date: 2014-09 · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: Sydney Water — Water System Planning Guideline
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-epa-age

Protecting Water Quality Through Water Age Management

US Environmental Protection Agency · Source date: 2022-04 · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: US Environmental Protection Agency — Protecting Water Quality Through Water Age Management
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-epa-survey

How to Conduct a Sanitary Survey of Drinking Water Systems

US Environmental Protection Agency · Source date: 2019-08 · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: US Environmental Protection Agency — How to Conduct a Sanitary Survey of Drinking Water Systems
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-epa-distribution

Drinking Water Distribution System Tools and Resources

US Environmental Protection Agency · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: US Environmental Protection Agency — Drinking Water Distribution System Tools and Resources
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-epa-pressure

Protecting Water Quality Through Distribution System Pressure Management

US Environmental Protection Agency · Source date: 2021-12 · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: US Environmental Protection Agency — Protecting Water Quality Through Distribution System Pressure Management
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-melbourne-sewers

Where your sewage goes

Melbourne Water · Source date: 2023-05-09 · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: Melbourne Water — Where your sewage goes
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-epa-wastewater

Municipal Wastewater

US Environmental Protection Agency · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: US Environmental Protection Agency — Municipal Wastewater
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-epa-primer

Primer for Municipal Wastewater Treatment Systems

US Environmental Protection Agency · Source date: 2004-09 · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: US Environmental Protection Agency — Primer for Municipal Wastewater Treatment Systems
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-wa-wastewater

How wastewater is treated

Water Corporation, Western Australia · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: Water Corporation, Western Australia — How wastewater is treated
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-melbourne-eastern

Eastern Treatment Plant

Melbourne Water · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: Melbourne Water — Eastern Treatment Plant
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-epa-biosolids

Basic Information about Sewage Sludge and Biosolids

US Environmental Protection Agency · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: US Environmental Protection Agency — Basic Information about Sewage Sludge and Biosolids
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-melbourne-digestion

Primary treatment of sewage and anaerobic treatment of sludge

Melbourne Water · Source date: 2016-05-25 · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: Melbourne Water — Primary treatment of sewage and anaerobic treatment of sludge
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-epa-reuse

Basic Information about Water Reuse

US Environmental Protection Agency · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: US Environmental Protection Agency — Basic Information about Water Reuse
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-cdc-reuse

Recycled Water for Drinking: An Overview

US Centers for Disease Control and Prevention · Source date: 2026-11-10 · Accessed: 2026-11-13

Rights / licence: Reference only. No permission to reuse source text, images, branding or diagrams is assumed; source assets are not reproduced.
Use in this guide: Factual reference for original explanations. No quotation or third-party visual asset is used.
Attribution: US Centers for Disease Control and Prevention — Recycled Water for Drinking: An Overview
Modifications: None to the source. Explanations and conceptual diagrams are newly authored.

water-epa-audits

Water Audits and Water Loss Control for Public Water Systems

US Environmental Protection Agency · Source date: 2013-07 · Accessed: 2026-11-13

Rights / licence: Reference only. No source-asset reuse permission is assumed or needed; source text and visual assets are not reproduced.
Use in this guide: Established water-balance terminology only; historical statistics and cost estimates are not adopted as current facts.
Attribution: US Environmental Protection Agency — Water Audits and Water Loss Control for Public Water Systems
Modifications: None to the source. New explanations and illustrative examples are original.

water-wa-loss

WUE: Leakage and Water Loss

Washington State Department of Health · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No source-asset reuse permission is assumed or needed; source text and visual assets are not reproduced.
Use in this guide: Factual reference for original explanations; no source text, images, diagrams or branding reproduced.
Attribution: Washington State Department of Health — WUE: Leakage and Water Loss
Modifications: None to the source. New explanations and illustrative examples are original.

water-epa-flow-monitoring

Leak Detection and Flow Monitoring Devices

US Environmental Protection Agency, WaterSense · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No source-asset reuse permission is assumed or needed; source text and visual assets are not reproduced.
Use in this guide: Factual reference for original explanations; no source text, images, diagrams or branding reproduced.
Attribution: US Environmental Protection Agency, WaterSense — Leak Detection and Flow Monitoring Devices
Modifications: None to the source. New explanations and illustrative examples are original.

water-epa-online-monitoring

Online Water Quality Monitoring Resources

US Environmental Protection Agency · Source date: 2026-09-21 · Accessed: 2026-11-13

Rights / licence: Reference only. No source-asset reuse permission is assumed or needed; source text and visual assets are not reproduced.
Use in this guide: Factual reference for original explanations; no source text, images, diagrams or branding reproduced.
Attribution: US Environmental Protection Agency — Online Water Quality Monitoring Resources
Modifications: None to the source. New explanations and illustrative examples are original.

water-epa-sensor-guidance

Online Water Quality Monitoring in Distribution Systems

US Environmental Protection Agency · Source date: 2018-04; second release 2019 · Accessed: 2026-11-13

Rights / licence: Reference only. No source-asset reuse permission is assumed or needed; source text and visual assets are not reproduced.
Use in this guide: Factual explanation of monitoring parameters, data validation and alert investigation. Publication and revision dates are distinguished in the document.
Attribution: US Environmental Protection Agency — Online Water Quality Monitoring in Distribution Systems
Modifications: None to the source. New explanations and illustrative examples are original.

water-epa-timeseries

Exploratory Analysis of Time-Series Data to Prepare for Real-Time Online Water Quality Monitoring

US Environmental Protection Agency · Source date: 2016-11 · Accessed: 2026-11-13

Rights / licence: Reference only. No source-asset reuse permission is assumed or needed; source text and visual assets are not reproduced.
Use in this guide: Factual reference for original explanations; no source text, images, diagrams or branding reproduced.
Attribution: US Environmental Protection Agency — Exploratory Analysis of Time-Series Data to Prepare for Real-Time Online Water Quality Monitoring
Modifications: None to the source. New explanations and illustrative examples are original.

water-seqwater-desalination

Desalination in South East Queensland: Fact Sheet

Seqwater · Source date: 2023-12 · Accessed: 2026-11-13

Rights / licence: Reference only. No source-asset reuse permission is assumed or needed; source text and visual assets are not reproduced.
Use in this guide: Process sequence used as a regional example only; expansion plans, historic output figures and broad environmental assurances are not adopted as current or universal claims.
Attribution: Seqwater — Desalination in South East Queensland: Fact Sheet
Modifications: None to the source. New explanations and illustrative examples are original.

water-corporation-desalination

How does water desalination work?

Water Corporation, Western Australia · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No source-asset reuse permission is assumed or needed; source text and visual assets are not reproduced.
Use in this guide: Reference for membrane desalination, concentrate handling and site-specific marine monitoring; promotional comparisons and numerical environmental claims are not reproduced.
Attribution: Water Corporation, Western Australia — How does water desalination work?
Modifications: None to the source. New explanations and illustrative examples are original.

water-epa-stormwater

Sources and Solutions: Stormwater

US Environmental Protection Agency · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No source-asset reuse permission is assumed or needed; source text and visual assets are not reproduced.
Use in this guide: Factual reference for original explanations; no source text, images, diagrams or branding reproduced.
Attribution: US Environmental Protection Agency — Sources and Solutions: Stormwater
Modifications: None to the source. New explanations and illustrative examples are original.

water-epa-green-infrastructure

About Green Infrastructure

US Environmental Protection Agency · Source date: 2026-09-11 · Accessed: 2026-11-13

Rights / licence: Reference only. No source-asset reuse permission is assumed or needed; source text and visual assets are not reproduced.
Use in this guide: Factual reference for original explanations; no source text, images, diagrams or branding reproduced.
Attribution: US Environmental Protection Agency — About Green Infrastructure
Modifications: None to the source. New explanations and illustrative examples are original.

water-epa-infiltration

Green Infrastructure and Groundwater Protection

US Environmental Protection Agency · Source date: 2026-02-10 · Accessed: 2026-11-13

Rights / licence: Reference only. No source-asset reuse permission is assumed or needed; source text and visual assets are not reproduced.
Use in this guide: Factual reference for original explanations; no source text, images, diagrams or branding reproduced.
Attribution: US Environmental Protection Agency — Green Infrastructure and Groundwater Protection
Modifications: None to the source. New explanations and illustrative examples are original.

water-usgs-desalination

Desalination

U.S. Geological Survey, Water Science School · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No source prose, photographs, diagrams or other assets reproduced.
Use in this guide: Supports the stable distinction between thermal evaporation/condensation and membrane desalination. Historical production figures, cost comparisons and simplified molecular descriptions are not adopted.
Attribution: U.S. Geological Survey, Water Science School, Desalination.
Modifications: Original explanatory prose; no source assets modified.

water-lbnl-desalination-energy

Volume 1: Survey of Available Information in Support of the Energy-Water Bandwidth Study of Desalination Systems

Lawrence Berkeley National Laboratory and U.S. Department of Energy · Source date: 2016-10 · Accessed: 2026-11-13

Rights / licence: Reference only. No source prose, photographs, diagrams or other assets reproduced.
Use in this guide: Supports the physical role of recovering pressure energy from reverse-osmosis concentrate. Historical efficiency percentages, costs and technology rankings are not adopted.
Attribution: Rao et al., Lawrence Berkeley National Laboratory, LBNL-1006424, October 2016.
Modifications: Original explanatory prose; no source assets modified.

Internet

isoc-how

How the Internet Works

Internet Society · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No text, photographs, or other assets reused; no blanket commercial asset license assumed.
Use in this guide: Technical facts checked for an independently written explanation. No source assets reused.
Attribution: Internet Society, How the Internet Works (Not stated).
Modifications: None to the source. All teaching prose and conceptual schematics are original.

isoc-properties

The Internet Way of Networking: Defining the critical properties of the Internet

Internet Society · Source date: 2020-09-09 · Accessed: 2026-11-13

Rights / licence: Reference only. No text, photographs, or other assets reused.
Use in this guide: Technical facts checked for an independently written explanation. No source assets reused.
Attribution: Internet Society, The Internet Way of Networking: Defining the critical properties of the Internet (2020-09-09).
Modifications: None to the source. All teaching prose and conceptual schematics are original.

rfc-1034

RFC 1034: Domain names — concepts and facilities

IETF / RFC Editor; P. Mockapetris · Source date: 1987-11 · Accessed: 2026-11-13

Rights / licence: Copyright holders and reuse terms are stated in the linked RFC. Reference only: no RFC prose, code, tables, or diagrams reproduced.
Use in this guide: Technical facts checked for an independently written explanation. No source assets reused.
Attribution: P. Mockapetris, RFC 1034: Domain names — concepts and facilities (1987-11).
Modifications: None to the source. All teaching prose and conceptual schematics are original.

rfc-1122

RFC 1122: Requirements for Internet Hosts — Communication Layers

IETF / RFC Editor; R. Braden (editor) · Source date: 1989-10 · Accessed: 2026-11-13

Rights / licence: Copyright holders and reuse terms are stated in the linked RFC. Reference only: no RFC prose, code, tables, or diagrams reproduced.
Use in this guide: Technical facts checked for an independently written explanation. No source assets reused.
Attribution: R. Braden (editor), RFC 1122: Requirements for Internet Hosts — Communication Layers (1989-10).
Modifications: None to the source. All teaching prose and conceptual schematics are original.

rfc-8200

RFC 8200: Internet Protocol, Version 6 (IPv6) Specification

IETF / RFC Editor; S. Deering and R. Hinden · Source date: 2017-07 · Accessed: 2026-11-13

Rights / licence: Copyright holders and reuse terms are stated in the linked RFC. Reference only: no RFC prose, code, tables, or diagrams reproduced.
Use in this guide: Technical facts checked for an independently written explanation. No source assets reused.
Attribution: S. Deering and R. Hinden, RFC 8200: Internet Protocol, Version 6 (IPv6) Specification (2017-07).
Modifications: None to the source. All teaching prose and conceptual schematics are original.

rfc-1812

RFC 1812: Requirements for IP Version 4 Routers

IETF / RFC Editor; F. Baker (editor) · Source date: 1995-06 · Accessed: 2026-11-13

Rights / licence: Copyright holders and reuse terms are stated in the linked RFC. Reference only: no RFC prose, code, tables, or diagrams reproduced.
Use in this guide: Technical facts checked for an independently written explanation. No source assets reused.
Attribution: F. Baker (editor), RFC 1812: Requirements for IP Version 4 Routers (1995-06).
Modifications: None to the source. All teaching prose and conceptual schematics are original.

rfc-4271

RFC 4271: A Border Gateway Protocol 4 (BGP-4)

IETF / RFC Editor; Y. Rekhter, T. Li, and S. Hares (editors) · Source date: 2006-01 · Accessed: 2026-11-13

Rights / licence: Copyright holders and reuse terms are stated in the linked RFC. Reference only: no RFC prose, code, tables, or diagrams reproduced.
Use in this guide: Technical facts checked for an independently written explanation. No source assets reused.
Attribution: Y. Rekhter, T. Li, and S. Hares (editors), RFC 4271: A Border Gateway Protocol 4 (BGP-4) (2006-01).
Modifications: None to the source. All teaching prose and conceptual schematics are original.

rfc-9293

RFC 9293: Transmission Control Protocol (TCP)

IETF / RFC Editor; W. Eddy (editor) · Source date: 2022-08 · Accessed: 2026-11-13

Rights / licence: Copyright holders and reuse terms are stated in the linked RFC. Reference only: no RFC prose, code, tables, or diagrams reproduced.
Use in this guide: Technical facts checked for an independently written explanation. No source assets reused.
Attribution: W. Eddy (editor), RFC 9293: Transmission Control Protocol (TCP) (2022-08).
Modifications: None to the source. All teaching prose and conceptual schematics are original.

rfc-768

RFC 768: User Datagram Protocol

IETF / RFC Editor; J. Postel · Source date: 1980-08 · Accessed: 2026-11-13

Rights / licence: Copyright holders and reuse terms are stated in the linked RFC. Reference only: no RFC prose, code, tables, or diagrams reproduced.
Use in this guide: Technical facts checked for an independently written explanation. No source assets reused.
Attribution: J. Postel, RFC 768: User Datagram Protocol (1980-08).
Modifications: None to the source. All teaching prose and conceptual schematics are original.

rfc-9000

RFC 9000: QUIC — A UDP-Based Multiplexed and Secure Transport

IETF / RFC Editor; J. Iyengar and M. Thomson (editors) · Source date: 2021-05 · Accessed: 2026-11-13

Rights / licence: Copyright holders and reuse terms are stated in the linked RFC. Reference only: no RFC prose, code, tables, or diagrams reproduced.
Use in this guide: Technical facts checked for an independently written explanation. No source assets reused.
Attribution: J. Iyengar and M. Thomson (editors), RFC 9000: QUIC — A UDP-Based Multiplexed and Secure Transport (2021-05).
Modifications: None to the source. All teaching prose and conceptual schematics are original.

rfc-9846

RFC 9846: The Transport Layer Security (TLS) Protocol Version 1.3

IETF / RFC Editor; E. Rescorla · Source date: 2026-07 · Accessed: 2026-11-13

Rights / licence: Copyright holders and reuse terms are stated in the linked RFC. Reference only: no RFC prose, code, tables, or diagrams reproduced.
Use in this guide: Technical facts checked for an independently written explanation. No source assets reused.
Attribution: E. Rescorla, RFC 9846: The Transport Layer Security (TLS) Protocol Version 1.3 (2026-07).
Modifications: None to the source. All teaching prose and conceptual schematics are original.

rfc-9110

RFC 9110: HTTP Semantics

IETF / RFC Editor; R. Fielding, M. Nottingham, and J. Reschke (editors) · Source date: 2022-06 · Accessed: 2026-11-13

Rights / licence: Copyright holders and reuse terms are stated in the linked RFC. Reference only: no RFC prose, code, tables, or diagrams reproduced.
Use in this guide: Technical facts checked for an independently written explanation. No source assets reused.
Attribution: R. Fielding, M. Nottingham, and J. Reschke (editors), RFC 9110: HTTP Semantics (2022-06).
Modifications: None to the source. All teaching prose and conceptual schematics are original.

rfc-9111

RFC 9111: HTTP Caching

IETF / RFC Editor; R. Fielding, M. Nottingham, and J. Reschke (editors) · Source date: 2022-06 · Accessed: 2026-11-13

Rights / licence: Copyright holders and reuse terms are stated in the linked RFC. Reference only: no RFC prose, code, tables, or diagrams reproduced.
Use in this guide: Technical facts checked for an independently written explanation. No source assets reused.
Attribution: R. Fielding, M. Nottingham, and J. Reschke (editors), RFC 9111: HTTP Caching (2022-06).
Modifications: None to the source. All teaching prose and conceptual schematics are original.

rfc-9114

RFC 9114: HTTP/3

IETF / RFC Editor; M. Bishop (editor) · Source date: 2022-06 · Accessed: 2026-11-13

Rights / licence: Copyright holders and reuse terms are stated in the linked RFC. Reference only: no RFC prose, code, tables, or diagrams reproduced.
Use in this guide: Technical facts checked for an independently written explanation. No source assets reused.
Attribution: M. Bishop (editor), RFC 9114: HTTP/3 (2022-06).
Modifications: None to the source. All teaching prose and conceptual schematics are original.

mdn-browser

Populating the page: how browsers work

MDN Web Docs / Mozilla contributors · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: MDN documentation is generally CC BY-SA 2.5 or later. Reference only: no source prose or images reproduced; independently written factual explanation.
Use in this guide: Technical facts checked for an independently written explanation. No source assets reused.
Attribution: MDN Web Docs / Mozilla contributors, Populating the page: how browsers work (Not stated).
Modifications: None to the source. All teaching prose and conceptual schematics are original.

icann-role

What Does ICANN Do?

ICANN · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. No source prose or assets reproduced; no blanket commercial asset license assumed.
Use in this guide: Technical facts checked for an independently written explanation. No source assets reused.
Attribution: ICANN, What Does ICANN Do? (Not stated).
Modifications: None to the source. All teaching prose and conceptual schematics are original.

rfc-9499

RFC 9499: DNS Terminology

IETF / RFC Editor; P. Hoffman and K. Fujiwara · Source date: 2024-03 · Accessed: 2026-11-13

Rights / licence: Copyright holders and reuse terms are stated in the linked RFC. Reference only: no RFC text, code, or diagrams reproduced.
Use in this guide: Technical reference supporting independently written explanations of DNS terminology and security distinctions.
Attribution: P. Hoffman and K. Fujiwara, RFC 9499: DNS Terminology (2024-03).
Modifications: None to source material. All prose and conceptual schematics are original.

rfc-4033

RFC 4033: DNS Security Introduction and Requirements

IETF / RFC Editor; R. Arends, R. Austein, M. Larson, D. Massey, and S. Rose · Source date: 2005-03 · Accessed: 2026-11-13

Rights / licence: Copyright holders and reuse terms are stated in the linked RFC. Reference only: no RFC text, code, or diagrams reproduced.
Use in this guide: Technical reference supporting independently written explanations of DNS terminology and security distinctions.
Attribution: R. Arends, R. Austein, M. Larson, D. Massey, and S. Rose, RFC 4033: DNS Security Introduction and Requirements (2005-03).
Modifications: None to source material. All prose and conceptual schematics are original.

rfc-8484

RFC 8484: DNS Queries over HTTPS (DoH)

IETF / RFC Editor; P. Hoffman and P. McManus · Source date: 2018-10 · Accessed: 2026-11-13

Rights / licence: Copyright holders and reuse terms are stated in the linked RFC. Reference only: no RFC text, code, or diagrams reproduced.
Use in this guide: Technical reference supporting independently written explanations of DNS terminology and security distinctions.
Attribution: P. Hoffman and P. McManus, RFC 8484: DNS Queries over HTTPS (DoH) (2018-10).
Modifications: None to source material. All prose and conceptual schematics are original.

corning-fibre

Optical Fiber Glossary of Terms

Corning Incorporated · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Reference only. Copyright and source-specific terms remain with the named authors or institution; no text, code, tables, images, or diagrams reproduced.
Use in this guide: Primary factual reference supporting independently written technical explanations and clearly labelled illustrative examples.
Attribution: Corning Incorporated, Optical Fiber Glossary of Terms (Not stated).
Modifications: None to source material. All prose, examples, and conceptual drawings are original.

nobel-fibre

The Nobel Prize in Physics 2009: Information for the Public

Royal Swedish Academy of Sciences · Source date: 2009 · Accessed: 2026-11-13

Rights / licence: Reference only. Copyright and source-specific terms remain with the named authors or institution; no text, code, tables, images, or diagrams reproduced.
Use in this guide: Primary factual reference supporting independently written technical explanations and clearly labelled illustrative examples.
Attribution: Royal Swedish Academy of Sciences, The Nobel Prize in Physics 2009: Information for the Public (2009).
Modifications: None to source material. All prose, examples, and conceptual drawings are original.

rfc-2681

RFC 2681: A Round-trip Delay Metric for IPPM

IETF / RFC Editor; G. Almes, S. Kalidindi, and M. Zekauskas · Source date: 1999-09 · Accessed: 2026-11-13

Rights / licence: Reference only. Copyright and source-specific terms remain with the named authors or institution; no text, code, tables, images, or diagrams reproduced.
Use in this guide: Primary factual reference supporting independently written technical explanations and clearly labelled illustrative examples.
Attribution: IETF / RFC Editor; G. Almes, S. Kalidindi, and M. Zekauskas, RFC 2681: A Round-trip Delay Metric for IPPM (1999-09).
Modifications: None to source material. All prose, examples, and conceptual drawings are original.

rfc-5681

RFC 5681: TCP Congestion Control

IETF / RFC Editor; M. Allman, V. Paxson, and E. Blanton · Source date: 2009-09 · Accessed: 2026-11-13

Rights / licence: Reference only. Copyright and source-specific terms remain with the named authors or institution; no text, code, tables, images, or diagrams reproduced.
Use in this guide: Primary factual reference supporting independently written technical explanations and clearly labelled illustrative examples.
Attribution: IETF / RFC Editor; M. Allman, V. Paxson, and E. Blanton, RFC 5681: TCP Congestion Control (2009-09).
Modifications: None to source material. All prose, examples, and conceptual drawings are original.

rfc-7567

RFC 7567: IETF Recommendations Regarding Active Queue Management

IETF / RFC Editor; F. Baker and G. Fairhurst (editors) · Source date: 2015-07 · Accessed: 2026-11-13

Rights / licence: Reference only. Copyright and source-specific terms remain with the named authors or institution; no text, code, tables, images, or diagrams reproduced.
Use in this guide: Primary factual reference supporting independently written technical explanations and clearly labelled illustrative examples.
Attribution: IETF / RFC Editor; F. Baker and G. Fairhurst (editors), RFC 7567: IETF Recommendations Regarding Active Queue Management (2015-07).
Modifications: None to source material. All prose, examples, and conceptual drawings are original.

etsi-5g-release15

ETSI TR 121 915 V15.0.0: Release description, Release 15

ETSI / 3GPP · Source date: 2019-10 · Accessed: 2026-11-13

Rights / licence: Reference only. Copyright and source-specific terms remain with the named authors or institution; no text, code, tables, images, or diagrams reproduced.
Use in this guide: Primary factual reference supporting independently written technical explanations and clearly labelled illustrative examples.
Attribution: ETSI / 3GPP, ETSI TR 121 915 V15.0.0: Release description, Release 15 (2019-10).
Modifications: None to source material. All prose, examples, and conceptual drawings are original.

etsi-5g-media

ETSI TR 126 919 V19.0.0: Study on media handling aspects of conversational services in 5G systems

ETSI / 3GPP · Source date: 2025-10 · Accessed: 2026-11-13

Rights / licence: Reference only. Copyright and source-specific terms remain with the named authors or institution; no text, code, tables, images, or diagrams reproduced.
Use in this guide: Primary factual reference supporting independently written technical explanations and clearly labelled illustrative examples.
Attribution: ETSI / 3GPP, ETSI TR 126 919 V19.0.0: Study on media handling aspects of conversational services in 5G systems (2025-10).
Modifications: None to source material. All prose, examples, and conceptual drawings are original.

Urban rail

rail-src-access

Plan an accessible journey

Transport for London · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: Transport for London
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-stepfree

Using TfL Go for step-free journeys

Transport for London · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: Transport for London
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-stations

Review of Transit Station Design Guidelines

National Academies of Sciences, Engineering, and Medicine / Transportation Research Board · Source date: 2026 · Accessed: 2026-11-13

Rights / licence: Copyright National Academy of Sciences. Factual reference only; no licensed figures or text reproduced.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: National Academies of Sciences, Engineering, and Medicine / Transportation Research Board
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-capacity

Transit Capacity and Quality of Service Manual, Third Edition, Chapter 8: Rail Transit Capacity

Transportation Research Board / National Academies · Source date: 2013 · Accessed: 2026-11-13

Rights / licence: Copyright National Academy of Sciences; reproduction permissions are limited. No source figures, tables or prose reused.
Use in this guide: Established relationship between station dwell, train separation and operating margin. This is an older edition, not a claim to be current design guidance.
Attribution: Transportation Research Board / National Academies
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-capacity-current

Transit Capacity and Quality of Service Manual, Fourth Edition

National Academies of Sciences, Engineering, and Medicine / Transportation Research Board · Source date: 2026 · Accessed: 2026-11-13

Rights / licence: Copyright National Academy of Sciences. No source figures, tables or prose reused.
Use in this guide: Current edition identified for further reading; our teaching scenario is an original simplification, not the manual’s engineering method.
Attribution: National Academies of Sciences, Engineering, and Medicine / Transportation Research Board
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-signals

Signals explained

Network Rail · Source date: 2018-09-05 · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: Network Rail
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-detection

Track circuits explained

Network Rail · Source date: 2019-09-30 · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: Network Rail
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-points

Signals and points failure

Network Rail · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: Network Rail
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-cbtc

20-Year Needs Assessment: New York City Transit appendix

Metropolitan Transportation Authority · Source date: 2023 · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: Metropolitan Transportation Authority
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-thirdrail

Third rail

Network Rail · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: Network Rail
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-overhead

Electrification

Network Rail · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: Network Rail
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-regen

Recycled energy on Tube trains (2)

London Assembly / Mayor of London · Source date: 2015-11-23 · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: London Assembly / Mayor of London
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-sleepers

A greener railway: more environmentally friendly sleepers

Network Rail · Source date: 2024-07-24 · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: Network Rail
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-track

Track treatment fleet

Network Rail · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: Network Rail
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-heat

Buckled rail and summer heat

Network Rail · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: Network Rail
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-timetable

The timetable

Network Rail · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: Network Rail
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-rules

Operational Rules

Network Rail · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: Network Rail
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-delays

Knock-on delays

Network Rail · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: Network Rail
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-information

How we keep you updated when there’s a delay

Network Rail · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: Network Rail
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-maintenance

Planned works

Network Rail · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference only; no text, photographs, maps, branding or diagrams reproduced.
Attribution: Network Rail
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-axles

Axle counting systems

Siemens Mobility · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Manufacturer’s description used for the basic counting mechanism only; no performance or promotional claims adopted.
Attribution: Siemens Mobility
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-fourthrail

London Underground: Safety Certification and Safety Authorisation, version 6.2

London Underground / Transport for London · Source date: 2022 · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Glossary evidence for the third- and fourth-conductor-rail arrangement only; no operational procedures reproduced.
Attribution: London Underground / Transport for London
Modifications: No source asset modified. Explanations and conceptual diagrams are original.

rail-src-depot-operations

Behind the scenes: Sydney Metro operations

Sydney Metro / Transport for NSW · Source date: 2022-08-24 · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Factual reference for stabling, operational staffing and train preparation. Historic service counts and future opening statements are not adopted as current facts.
Attribution: Sydney Metro / Transport for NSW
Modifications: No source asset modified. Explanations, examples and conceptual diagrams are original.

rail-src-depot-south

Construction completed at Sydney Metro Trains Facility South

Sydney Metro / Transport for NSW · Source date: 2024-06 · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Completed facility functions: stabling, cleaning, light maintenance and water management. No photographs, drawings or claimed future service dates reproduced.
Attribution: Sydney Metro / Transport for NSW
Modifications: No source asset modified. Explanations, examples and conceptual diagrams are original.

rail-src-turnbacks

Through-Running Regional Rail: Results, section 9, Turnback Operations

National Academies of Sciences, Engineering, and Medicine / Transportation Research Board · Source date: 2026 · Accessed: 2026-11-13

Rights / licence: Copyright National Academy of Sciences; no source figures, tables or prose reused.
Use in this guide: Reference for terminal occupation, recovery allowance and turnbacks as capacity constraints; regional-rail context identified. No source tables or illustrations reproduced.
Attribution: National Academies of Sciences, Engineering, and Medicine / Transportation Research Board
Modifications: No source asset modified. Explanations, examples and conceptual diagrams are original.

rail-src-hunter-turnback

Hunter Street Station Newsletter: turnback tunnels

Sydney Metro / Transport for NSW · Source date: 2024-06 · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Illustrates the purpose of a planned turnback beyond a station. Construction-era description; no claim that the project is currently open. No source artwork reused.
Attribution: Sydney Metro / Transport for NSW
Modifications: No source asset modified. Explanations, examples and conceptual diagrams are original.

rail-src-ventilation-crossrail

Information Paper A4: Ventilation and Intervention Shafts, version 2

Crossrail · Source date: 2007-11-20 · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Historical planning document used for the distinction between ventilation, pressure relief, comfort and smoke-control objectives. Not current operational guidance. No drawings or safety procedures reproduced.
Attribution: Crossrail
Modifications: No source asset modified. Explanations, examples and conceptual diagrams are original.

rail-src-ventilation-central

Aboriginal artwork adorns Central Station ventilation buildings

Sydney Metro / Transport for NSW · Source date: 2022-09-15 · Accessed: 2026-11-13

Rights / licence: Copyright and artwork rights remain with their respective owners; no asset reuse permission assumed or required for this factual reference.
Use in this guide: Only the stated ventilation function of the buildings informs the explanation. No photographs, artwork, cultural designs or artist quotations are reused.
Attribution: Sydney Metro / Transport for NSW
Modifications: No source asset modified. Explanations, examples and conceptual diagrams are original.

rail-src-thermal-design

The Design of Thermal Tunnel Energy Segments for Crossrail

Duncan P Nicholson, Qing Chen, Mike de Silva, Alan Winter and Ralf Winterling; Crossrail Learning Legacy / ICE Publishing · Source date: 2014-11-03 · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Reference for train heat sources and the distinction between ventilation and other heat-management approaches. A design study, not a claim of deployment. No figures, equations or prose copied.
Attribution: Duncan P Nicholson, Qing Chen, Mike de Silva, Alan Winter and Ralf Winterling; Crossrail Learning Legacy / ICE Publishing
Modifications: No source asset modified. Explanations, examples and conceptual diagrams are original.

rail-src-flooding

Flooding

Network Rail · Source date: Not stated · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Reference for water effects on track support, power and signalling and the need for inspection after water recedes. No photos or operational thresholds reproduced.
Attribution: Network Rail
Modifications: No source asset modified. Explanations, examples and conceptual diagrams are original.

rail-src-adaptation

Fourth Adaptation Report

Network Rail · Source date: 2024-12 · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Reference for connected weather risks and location-specific adaptation involving drainage and neighbouring infrastructure. No statistical charts, tables or source artwork reproduced.
Attribution: Network Rail
Modifications: No source asset modified. Explanations, examples and conceptual diagrams are original.

rail-src-asset-weather

Asset Management: Weather Resilience and Climate Change Adaptation Plan

Network Rail · Source date: 2021-05 · Accessed: 2026-11-13

Rights / licence: Copyright retained by the source institution; no asset reuse licence relied upon.
Use in this guide: Reference for drainage, water ingress and finite pumping capacity under extreme conditions. Historical risk-planning document, not current operating instructions. No figures or prose reproduced.
Attribution: Network Rail
Modifications: No source asset modified. Explanations, examples and conceptual diagrams are original.

Across systems

city-src-cisa-irpf

Infrastructure Resilience Planning Framework (IRPF)

Cybersecurity and Infrastructure Security Agency (CISA) · Source date: 2025-03 · Accessed: 2026-11-14

Rights / licence: U.S. federal government publication; third-party material and marks may have separate rights. No source asset reuse licence is relied upon.
Use in this guide: Factual reference for dependencies, backup resources, resilience and recovery considerations, especially pages 4, 21–22 and 28. The fictional city, causal sequences and glossary wording are original; no source diagrams, tables or prose are reproduced.
Attribution: Cybersecurity and Infrastructure Security Agency, Infrastructure Resilience Planning Framework, March 2025.
Modifications: No source asset modified. All explanatory text and teaching scenarios are independently authored.

city-src-epa-power-resilience

Power Resilience Guide for Water and Wastewater Utilities

U.S. Environmental Protection Agency, Office of Water · Source date: 2023-05-03 · Accessed: 2026-11-14

Rights / licence: U.S. federal government publication; third-party material and marks may have separate rights. No source asset reuse licence is relied upon.
Use in this guide: Factual reference for electricity-dependent water and wastewater equipment, limits of backup support, communications and cross-utility recovery. EPA's resource page dates this updated file 3 May 2023; its cover is dated March 2023. No generator instructions, operating procedures, case-study figures or source artwork are reproduced.
Attribution: U.S. Environmental Protection Agency, Power Resilience Guide for Water and Wastewater Utilities, EPA 810-F-23-013, 2023.
Modifications: No source asset modified. The fictional layouts, outcomes and arithmetic are original illustrative assumptions.

city-src-ofcom-weather

Stay connected in severe weather

Ofcom · Source date: 2026-10-22 · Accessed: 2026-11-14

Rights / licence: Copyright retained by Ofcom and other respective rights holders. No source asset reuse licence is relied upon.
Use in this guide: Factual reference for the electrical dependence of home broadband equipment and possible weather impacts on communications networks. UK-specific consumer entitlements, emergency-call advice and backup durations are not generalized or reproduced.
Attribution: Ofcom, Stay connected in severe weather, updated 22 October 2026.
Modifications: No source asset modified. All explanations and fictional examples are original.

Glossary references

glossary-src-rfc5136

RFC 5136: Defining Network Capacity

P. Chimento and J. Ishac / Internet Engineering Task Force (IETF) · Source date: 2008-02 · Accessed: 2026-11-14

Rights / licence: Copyright The IETF Trust (2008); source publication carries its own rights notices. No source text or figure reuse licence is relied upon.
Use in this guide: Factual reference for the ambiguity of bandwidth, measurement-layer distinctions, network capacity and limiting links. The glossary uses independently written plain-language definitions and original illustrative examples, not copied protocol text.
Attribution: P. Chimento and J. Ishac, RFC 5136: Defining Network Capacity, IETF, February 2008.
Modifications: No source asset modified. All prose and accompanying teaching illustrations are original.

Original asset register

Connected city cutaway

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — city().
Published location: /
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Redrawn for edition 1.3 as a black/white/yellow public-works atlas: crisp architectural outlines, neutral grey depth planes, numbered network labels and distinct solid, double, dashed and sleeper-mark routes. Network meanings and highlight/animation controls retained. Original project artwork; no third-party artwork incorporated.

Electricity symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(electricity).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Water symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(water).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Internet symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(internet).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Rail symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(rail).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Arrow symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(arrow).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Search symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(search).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Generator symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(generator).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Tower symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(tower).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Transformer symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(transformer).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Home symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(home).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Valve symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(valve).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Tank symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(tank).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Server symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(server).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Device symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(device).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Router symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(router).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Signal symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(signal).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Station symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(station).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Clock symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(clock).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Network symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon(network).
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Electricity system diagram

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/build.mjs — diagram().
Published location: /systems/electricity/#map
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Electricity scenario graphic

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: public/assets/model-views.js — modelView().
Published location: /scenarios/#lab-electricity
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Interactive and pre-rendered explanatory diagram with accessible description, on the family page and what-if lab. Includes an expanded inspection view.
Attribution: No external attribution required.
Modifications: Expanded in edition 1.1 with labelled SVG schematics, visual scales for the illustrative equations, baseline comparisons and full-size inspection. Restyled for edition 1.3 as black/white/yellow square diagrams; the illustrative calculations, scales, assumptions and comparison behaviour are retained. Original project artwork; no external assets incorporated. The edition 1.4 diagram responds to demand and available upward headroom; its capacity threshold and supply/demand bars update with both inputs. A/B comparison reports both chosen inputs and the resulting metrics. All values are original teaching assumptions; no external artwork was incorporated.

Water system diagram

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/build.mjs — diagram().
Published location: /systems/water/#map
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Water scenario graphic

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: public/assets/model-views.js — modelView().
Published location: /scenarios/#lab-water
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Interactive and pre-rendered explanatory diagram with accessible description, on the family page and what-if lab. Includes an expanded inspection view.
Attribution: No external attribution required.
Modifications: Expanded in edition 1.1 with labelled SVG schematics, visual scales for the illustrative equations, baseline comparisons and full-size inspection. Restyled for edition 1.3 as black/white/yellow square diagrams; the illustrative calculations, scales, assumptions and comparison behaviour are retained. Original project artwork; no external assets incorporated. The edition 1.4 diagram responds to elapsed outage time and demand, keeping 600 m³ initial usable storage and zero inflow. Reservoir level, drawdown curve, depletion time and A/B metrics update consistently. All values are original teaching assumptions; no external artwork was incorporated.

Internet system diagram

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/build.mjs — diagram().
Published location: /systems/internet/#map
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Internet scenario graphic

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: public/assets/model-views.js — modelView().
Published location: /scenarios/#lab-internet
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Interactive and pre-rendered explanatory diagram with accessible description, on the family page and what-if lab. Includes an expanded inspection view.
Attribution: No external attribution required.
Modifications: Expanded in edition 1.1 with labelled SVG schematics, visual scales for the illustrative equations, baseline comparisons and full-size inspection. Restyled for edition 1.3 as black/white/yellow square diagrams; the illustrative calculations, scales, assumptions and comparison behaviour are retained. Original project artwork; no external assets incorporated. The edition 1.4 diagram responds to preferred-link availability and an assigned one-way delay for the alternate path. Reachability and the chosen delay remain distinct; A/B comparison records both inputs and results. All values are original teaching assumptions; no external artwork was incorporated.

Rail system diagram

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/build.mjs — diagram().
Published location: /systems/rail/#map
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for this edition; no third-party artwork incorporated.

Rail scenario graphic

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: public/assets/model-views.js — modelView().
Published location: /scenarios/#lab-rail
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Interactive and pre-rendered explanatory diagram with accessible description, on the family page and what-if lab. Includes an expanded inspection view.
Attribution: No external attribution required.
Modifications: Expanded in edition 1.1 with labelled SVG schematics, visual scales for the illustrative equations, baseline comparisons and full-size inspection. Restyled for edition 1.3 as black/white/yellow square diagrams; the illustrative calculations, scales, assumptions and comparison behaviour are retained. Original project artwork; no external assets incorporated. The edition 1.4 diagram responds to repeated added dwell and the planned interval. Occupation blocks, resulting headway, available margin and A/B metrics reflect both inputs. All values are original teaching assumptions; no external artwork was incorporated.

Connection mark / favicon

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: public/assets/favicon.svg.
Published location: /assets/favicon.svg
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Restyled for edition 1.3 as the original black connection mark on an opaque #FFD400 yellow square. Network geometry retained; no third-party artwork incorporated.

Energy storage symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon("battery").
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for expanded edition 1.1; no third-party artwork incorporated.

AC waveform symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon("wave").
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for expanded edition 1.1; no third-party artwork incorporated.

Measurement gauge symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon("meter").
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for expanded edition 1.1; no third-party artwork incorporated.

Solar panel symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon("solar").
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for expanded edition 1.1; no third-party artwork incorporated.

Ventilation symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon("fan").
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for expanded edition 1.1; no third-party artwork incorporated.

Railway depot symbol

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/visuals.mjs — icon("depot").
Published location: System, component and navigation interfaces
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Drawn originally for expanded edition 1.1; no third-party artwork incorporated.

Browser ICO icon

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/icons.mjs + public/assets/favicon.svg.
Published location: /favicon.ico
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Browser or device icon derived from the original project network mark.
Attribution: No external attribution required.
Modifications: Rasterised the edition 1.3 original black connection mark on its opaque #FFD400 yellow square into 16-, 32- and 48-pixel PNG frames in one ICO container. No third-party artwork incorporated.

32-pixel browser icon

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/icons.mjs + public/assets/favicon.svg.
Published location: /assets/favicon-32.png
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Browser or device icon derived from the original project network mark.
Attribution: No external attribution required.
Modifications: Rasterised the edition 1.3 original black connection mark on its opaque #FFD400 yellow square into a 32-pixel PNG. No third-party artwork incorporated.

192-pixel application icon

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/icons.mjs + public/assets/favicon.svg.
Published location: /assets/icon-192.png
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Browser or device icon derived from the original project network mark.
Attribution: No external attribution required.
Modifications: Rasterised the edition 1.3 original black connection mark on its opaque #FFD400 yellow square into a 192-pixel PNG. No third-party artwork incorporated.

Apple touch icon

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-13
Original URL: Not applicable: original project artwork. Source: scripts/icons.mjs + public/assets/favicon.svg.
Published location: /assets/apple-touch-icon.png
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Browser or device icon derived from the original project network mark.
Attribution: No external attribution required.
Modifications: Rasterised the edition 1.3 original black connection mark on its opaque #FFD400 yellow square into a 180-pixel Apple touch PNG. The source square supplies the visible opaque background; no third-party artwork incorporated.

Connected-city dependency model diagram

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: public/assets/city-model.js — cityGraphic() / cityView().
Published location: /scenarios/#lab-city
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4: four service nodes, directed dependency links, textual states and original black/white/yellow geometry. The diagram changes with the chosen incident, elapsed time, resilience profile and restored-now snapshot. Companion panels, timeline and ephemeral A/B comparison explain the model. All quantities, exposure rules and recovery gates are editorial teaching assumptions, not source-derived standards or measured events. No source diagrams or artwork incorporated.

Headway glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("headway").
Published location: /glossary/#headway
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for headway, paired with an original caption and the existing project clock symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. Headway separates trains; dwell measures one train's time at a stop. No third-party artwork incorporated.

Dwell time glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("dwell").
Published location: /glossary/#dwell
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for dwell time, paired with an original caption and the existing project station symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. A longer dwell does not always reduce throughput; it must become a limiting constraint. No third-party artwork incorporated.

Latency glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("latency").
Published location: /glossary/#latency
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for latency, paired with an original caption and the existing project clock symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. Latency is elapsed time; bandwidth describes a data-carrying rate. No third-party artwork incorporated.

Bandwidth glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("bandwidth").
Published location: /glossary/#bandwidth
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for bandwidth, paired with an original caption and the existing project network symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. Networking usage differs from radio-frequency bandwidth, which is a frequency range measured in hertz. No third-party artwork incorporated.

Packet glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("packet").
Published location: /glossary/#packet
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for packet, paired with an original caption and the existing project router symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. A packet is a delivery unit, not necessarily a complete message, page or file. No third-party artwork incorporated.

Capacity glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("capacity").
Published location: /glossary/#capacity
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for capacity, paired with an original caption and the existing project meter symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. Capacity is an available limit; actual use or throughput may be lower. No third-party artwork incorporated.

Power glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("power").
Published location: /glossary/#power
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for power, paired with an original caption and the existing project electricity symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. Power is a rate; energy is the accumulated amount transferred or stored. No third-party artwork incorporated.

Energy glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("energy").
Published location: /glossary/#energy
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for energy, paired with an original caption and the existing project battery symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. A kilowatt-hour measures energy; a kilowatt measures power. No third-party artwork incorporated.

Electrical frequency glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("frequency").
Published location: /glossary/#frequency
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for electrical frequency, paired with an original caption and the existing project wave symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. Electrical frequency is different from train service frequency, such as departures per hour. No third-party artwork incorporated.

Inertia glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("inertia").
Published location: /glossary/#inertia
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for inertia, paired with an original caption and the existing project generator symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. Fast controlled response from an inverter is not automatically the same physical mechanism as rotating inertia. No third-party artwork incorporated.

Water pressure glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("pressure").
Published location: /glossary/#pressure
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for water pressure, paired with an original caption and the existing project meter symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. Pressure is not stored volume or flow rate, and it does not certify water quality. No third-party artwork incorporated.

Water flow rate glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("flow").
Published location: /glossary/#flow
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for water flow rate, paired with an original caption and the existing project valve symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. Flow rate describes volume per time; pressure describes force per area. No third-party artwork incorporated.

Storage glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("storage").
Published location: /glossary/#storage
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for storage, paired with an original caption and the existing project tank symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. An inventory does not by itself establish deliverable pressure, power or service quality. No third-party artwork incorporated.

Resilience glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("resilience").
Published location: /glossary/#resilience
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for resilience, paired with an original caption and the existing project network symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. Resilience does not mean immunity to failure or an unlimited backup supply. No third-party artwork incorporated.

Redundancy glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("redundancy").
Published location: /glossary/#redundancy
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for redundancy, paired with an original caption and the existing project network symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. Two lines on a diagram do not prove independent, functioning alternatives. No third-party artwork incorporated.

Dependency glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("dependency").
Published location: /glossary/#dependency
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for dependency, paired with an original caption and the existing project arrow symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. A dependency can be one-way; interdependency describes mutual reliance. No third-party artwork incorporated.

Buffer glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("buffer").
Published location: /glossary/#buffer
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for buffer, paired with an original caption and the existing project tank symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. A buffer delays or absorbs an effect within limits; it does not remove the underlying constraint. No third-party artwork incorporated.

Bottleneck glossary illustration

Author / institution: Invisible Infrastructure project, with AI assistance
Source date: 2026-11-14
Original URL: Not applicable: original project artwork. Source: scripts/glossary-template.mjs — termIllustration("bottleneck").
Published location: /glossary/#bottleneck
Rights / licence: Original project artwork; no third-party asset restrictions identified. No exclusive copyright claim is made for AI-assisted output.
Usage: Explanatory visual for this project, including its intended commercial website use. Not documentary evidence.
Attribution: No external attribution required.
Modifications: Created originally for edition 1.4 as an inline conceptual SVG for bottleneck, paired with an original caption and the existing project station symbol from scripts/visuals.mjs. Geometry is illustrative and not to scale; it is not documentary evidence or a reproduced source figure. The busiest-looking component is not necessarily the constraint limiting the whole service. No third-party artwork incorporated.

Locally hosted typefaces

Anton supplies the condensed display voice; Outfit keeps explanations and controls readable. These fonts were obtained independently from their official open-source distribution, with the full licence notices retained. No embedded fonts were extracted from the design reference.

Anton

The Anton Project Authors · Consulted 2026-11-13 · Source date: Not stated

Original source: Official font binary ↗
Licence: SIL Open Font License 1.1 — Read the full notice
Attribution: Copyright 2020 The Anton Project Authors (https://github.com/googlefonts/AntonFont.git)
Modifications: None. Original TrueType binary downloaded unchanged; local filename normalised. No PDF fonts extracted.

Outfit

The Outfit Project Authors · Consulted 2026-11-13 · Source date: Not stated

Original source: Official font binary ↗
Licence: SIL Open Font License 1.1 — Read the full notice
Attribution: Copyright 2021 The Outfit Project Authors (https://github.com/Outfitio/Outfit-Fonts)
Modifications: None. Original TrueType binary downloaded unchanged; local filename normalised. No PDF fonts extracted.

Anton

The Anton Project Authors · Consulted 2026-11-13 · Source date: Not stated

Original source: Official font binary ↗
Licence: SIL Open Font License 1.1 — Read the full notice
Attribution: Copyright 2020 The Anton Project Authors (https://github.com/googlefonts/AntonFont.git)
Modifications: Converted the original TrueType font to WOFF2 using fontTools 4.68.0 and Brotli 1.2.1. No subsetting, glyph design, glyph ordering, character mapping, or horizontal metric changes. Original font names and copyright metadata retained.

Outfit

The Outfit Project Authors · Consulted 2026-11-13 · Source date: Not stated

Original source: Official font binary ↗
Licence: SIL Open Font License 1.1 — Read the full notice
Attribution: Copyright 2021 The Outfit Project Authors (https://github.com/Outfitio/Outfit-Fonts)
Modifications: Converted the original TrueType font to WOFF2 using fontTools 4.68.0 and Brotli 1.2.1. No subsetting, glyph design, glyph ordering, character mapping, or horizontal metric changes. Original font names and copyright metadata retained.