What penalty is incurred after 5 seconds of missed communication between the RCT and the RCL?

The correct answer is based on the established safety protocols within the context of remote control operations. After 5 seconds of missed communication between the Remote Control Train (RCT) and the Remote Control Locomotive (RCL), a full service brake application is automatically initiated. This procedure is critical because it ensures the safety of the train and its surroundings by bringing the locomotive to a stop, preventing potential accidents that may arise from the loss of control.

The implementation of this safety measure demonstrates the priority placed on maintaining constant communication in rail operations. If communication fails, the risk of unintended movement or operational errors increases significantly. Thus, the automatic application of the brakes serves as a failsafe mechanism to protect both personnel and equipment, ensuring that the train halts until communication is reestablished or the issue is resolved.

Other options, while they may imply some form of penalty or consequence, do not effectively address the immediate safety needs that arise from communication failure.