🚇 Engineering Underground Transit Hubs

About this simulation

Deep multimodal transit hubs stack a street-level concourse, a mezzanine, a metro platform and often a freight or through-running tunnel bore on top of one another. Every extra metre of depth buys separation from utilities and other lines, but it also adds vertical travel distance that every passenger — and every evacuee in a fire or smoke event — must cover on foot, by escalator or by stair.

How it works

• Evacuation time is estimated as escalator travel time (depth ÷ nominal rise speed) plus a queueing delay at the stair/escalator cores, following the logic behind life-safety codes such as NFPA 130's platform-clearance rule.
• Egress capacity scales with the number of independent stair/escalator cores — a second core roughly doubles throughput and shortens queueing delay.
• Ventilation airflow is modest in normal operation but must jump sharply in smoke-extraction mode to hold a tenable escape path, scaling with both depth and passenger heat load.
• Small figures animate along the escalator inclines, illustrating pedestrian flow between the platform, mezzanine and street; in emergency mode they all funnel upward along the highlighted evacuation route.

Controls

• Station depth — platform depth below street level (20–70m).
• Peak passenger load — passengers present at the platform level who would need to clear the hub.
• Egress design — one or two independent stair/escalator cores serving the platform.
• Emergency smoke-extraction mode — switches ventilation from normal supply to high-rate smoke extraction and reroutes all pedestrian flow upward along the evacuation path.
• ↺ Reset flow — restarts the pedestrian animation. Drag to rotate, scroll to zoom.

Did you know?

Many metro codes require platforms to clear within about four to six minutes and the whole station within about six to eight minutes, even during an equipment failure — a benchmark that directly drives how deep, and how many escape cores, a station design is allowed to have.