Scores are relative 0–100 marks within this atlas. Use them to browse, not as an engineering spec.
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Quick answers
Which local authority or corridor rules matter for this type?
Start with the local lens: type approval, operator licences and the hubs named on this page — not a single global checklist.
Is this a buying guide?
No. Tool-Lifes /vehicles is an educational atlas. It explains history, systems and culture without affiliate rankings.
Are the scores official?
No. The six scores are relative editorial 0–100 marks across the twenty-four types on this site.
Where do the photos come from?
Lead images resolve from Wikimedia Commons via Wikipedia titles on the English masters, with licences recorded on the credits page.
Why metric units?
Metric is the default. Regional notes (US customary, local brand culture) appear in culture and market chapters.
How is this different from a wiki article?
Each type gets seven fixed-depth chapters, comparable scores and cross-type labs — structured for browsing, not a single freeform page.
Every Subway is a negotiated stack of structure, energy conversion, control and human interfaces under weather and regulation.
The systems, meters and hotspots below are type-level engineering — manufacturers vary; load paths and failure modes do not.
Systems
Steel or aluminum trainset
Multiple-unit cars share traction and braking; walk-through gangways increase usable capacity.
Third-rail or shoegear
Contact shoes pick up 750 V DC (typical) from third rail or overhead in some systems.
CBTC moving block
Communication-based train control shrinks headway by tracking train positions dynamically.
Platform screen doors
PSDs interlock with train doors to prevent falls and improve climate control.
Emergency ventilation
Tunnel fans and shaft dampers manage smoke during underground incidents.
Crowd density & PA
CCTV and load weighing inform dispatch; automated announcements cycle stops.
Relative meters
Hotspots
Third-rail insulators
Track fires and shoe loss occur when insulators fail or debris bridges rails.
Door motor gearboxes
Misaligned doors block CBTC departure interlocks and swell dwell.
Brake pad/disc wear
Squeal and longer stopping distances appear before minimum thickness.
Tunnel drainage
Pump failures flood low points and trigger speed restrictions.
Signal radio drops
CBTC handoffs fail in metal tunnel nulls without leaky feeder coverage.
Materials
Stainless steel car shells
Corrosion resistance in humid tunnels extends service life.
Phenolic third-rail covers
Insulating covers protect maintenance staff from live rail.
Sintered brake blocks
Low-noise compositions reduce wayside squeal in stations.
Halogen-free cable insulation
Low-smoke cables reduce toxic load during tunnel fires.
Keep exploring
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Overall 53