Which tripped MCBs will result in an emergency brake application?

The correct answer encompasses both friction brake monitoring and the safety loop with emergency brake valve due to their critical roles in ensuring the safety and effective operation of train systems.

Friction brake monitoring systems are designed to detect any discrepancies or failures in the braking mechanism that could lead to a loss of control. When these systems identify issues, they can trigger a trip in the motor circuit breaker (MCB), which consequently initiates an emergency brake application to prevent potential accidents.

Similarly, the safety loop, which often includes components like emergency brake valves, is essential in monitoring the integrity of the braking system. If the safety loop detects a failure or interruption, it activates the emergency brake to ensure that the train can stop safely.

Together, these two systems represent crucial fail-safes in train operation, and when either one of them triggers a trip, it leads to an emergency brake application. This protective measure helps ensure the safety of the train and passengers, reinforcing the importance of both friction brake monitoring and the safety loop in fault detection and response scenarios.

The other options do not encompass the same safety protocols that directly contribute to emergency braking procedures in the context of tripped MCBs, illustrating the specific roles that friction brake monitoring and safety loops play in maintaining operational