What is indicated on the CBTC-TOD when approaching a flashing red order signal?

When approaching a flashing red order signal, it indicates that the train engineer must call for orders. This signal is a directive for the engineer to seek further instructions from dispatch or control. The flashing red order signal is a crucial warning that signifies there may be conditions or situations that require clarification before proceeding, ensuring the safety of the operation.

In this context, other responses like proceeding with caution or stopping immediately do not accurately capture the intention of the flashing red order signal. Additionally, switching to MCS (Manual Control System) mode is not the appropriate action required when presented with this type of signal, as the primary step is to communicate with dispatch for further guidance. Thus, calling for orders is a necessary protocol to ensure safety and proper train operation in response to a flashing red order signal.