What operating mode should a train switch to after an ATC failure in CBTC territory?

When an Automatic Train Control (ATC) failure occurs in a Communication-Based Train Control (CBTC) territory, the system typically advises switching to ATC Bypass mode. This mode allows trains to continue operating without the full functionality of the ATC system while still maintaining some level of safety and operational integrity.

In ATC Bypass mode, the train is equipped to manage its speed and stops, but will not receive real-time updates from the control system. This mode is designed specifically for scenarios where a train must still function safely despite an ATC failure. It enables trains to proceed at a reduced speed and operate under defined limits, while ensuring that they do not encounter obstacles or hazards that could lead to unsafe conditions.

Choosing this mode after an ATC failure reflects a safety-first approach, as it provides flexibility in operations while still safeguarding passengers and personnel. The alternative options may involve either halting operations entirely or initiating manual control, which may not be feasible or safe under every circumstance.