What operating mode is used after an ATC failure in CBTC territory?

In the context of Communication-Based Train Control (CBTC) systems, after an Automatic Train Control (ATC) failure, the operating mode typically transitions to an ATC Bypass mode. This mode is specifically designed for scenarios where the automated control system is inoperative, allowing train operations to continue safely without relying on the automatic functions of the system.

By employing ATC Bypass, train engineers can manually control train functions while still adhering to safety protocols and operational limits. This ensures that essential functionalities are maintained, and the trains can be operated under specified conditions, minimizing the impact of the failure.

In contrast, normal mode and service mode are typically associated with standard operations where the system is functioning correctly. Manual mode does allow for train operation without automation, but ATC Bypass provides a more structured approach for managing the specific circumstances following an ATC failure, ensuring that safety measures are in place while still facilitating train movement.