Every subway is a stack of systems that must agree under load, weather and regulation.
Meters below are relative within this atlas; hotspots name the parts riders and engineers argue about first.
Systems
Structure
The structure of a subway sets limits on performance, upkeep and passenger experience.
Propulsion
The propulsion of a subway sets limits on performance, upkeep and passenger experience.
Energy store
The energy store of a subway sets limits on performance, upkeep and passenger experience.
Control
The control of a subway sets limits on performance, upkeep and passenger experience.
Passenger interface
The passenger interface of a subway sets limits on performance, upkeep and passenger experience.
Safety systems
The safety systems of a subway sets limits on performance, upkeep and passenger experience.
Relative meters
Hotspots
Primary structure
Frames, hulls, fuselages or beams that carry static and dynamic loads.
Propulsion core
Engines, motors, rotors or sails that produce useful motion.
Energy path
Fuel tanks, batteries, catenary or cables that feed propulsion.
Human interface
Controls, cabins, decks or cockpits where people command the vehicle.
Protection layer
Brakes, redundancy, life-support or crash structures that buy time when something fails.
Materials
Structural metals
Steel and aluminium alloys remain common where cost and reparability matter.
Composites
Carbon and glass fibre cut weight when certification and inspection keep pace.
Polymers & elastomers
Seals, tyres, fairings and interiors manage weather, vibration and touchpoints.
Conductors & semiconductors
Wiring, power electronics and sensors turn raw power into controllable motion.
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