Which mode would trigger an absence of Trip ID?

In the scenario where an absence of Trip ID is triggered, ATC Bypass mode is identified as the correct choice due to its specific function within the system’s operations. ATC (Automatic Train Control) Bypass mode is utilized when certain safety or operational protocols are suspended to allow for maintenance or specific testing protocols. In this mode, the usual tracking and identification protocols that generate a Trip ID are disabled, as the system is operating outside its standard parameters.

The purpose of this mode is often to perform work on the train's systems without the interference of automatic safety features that could otherwise impede those maintenance tasks. As a result, the system does not generate a Trip ID during this mode, marking it distinctly different from the other operational modes, such as Normal operation, Crew training, and Routine inspection, all of which typically require a Trip ID for tracking and safety compliance purposes.