When a non-fixed signal is given to stop a train, how must it be acknowledged?

When a non-fixed signal is given to stop a train, the acknowledgment of this stop signal must be performed by sounding Rule 14A (OO). This rule specifies the proper action that a train crew must take when responding to a non-fixed signal, ensuring clear communication and compliance with safety protocols.

The sound of Rule 14A (OO) serves as a recognition of the signal, indicating to both the crew and any observing personnel that the signal has been acknowledged and that appropriate actions are being taken. This method of acknowledgment is critical in maintaining a consistent protocol for train operations, which is vital for safety and coordination within the transit system.

Using visual signals, like waving a flag, or direct communication with dispatch may not provide the same level of clarity and protocol adherence necessary in a dynamic rail environment. Sounding Rule 14B (OOO) is not applicable in this context, as it pertains to a different scenario involving movement rather than stopping. Thus, sounding Rule 14A (OO) is the correct and established method to acknowledge the stop signal.