Which rules are observed when a train operates against the current of traffic?

When a train operates against the current of traffic, it is essential to follow the Manual Block Signal System rules. The Manual Block Signal System is specifically designed to provide the necessary safety protocols and operational guidelines for situations where trains might be moving in opposite directions, particularly in areas where track occupancy needs to be carefully monitored.

In this context, the Manual Block Signal System allows for clearer communication and ensures that train movements can be safely coordinated. It takes into account particular signaling aspects that are required when a train is moving contrary to normal traffic flow, thus maintaining safe and efficient operations.

The other options encompass rules that are not specifically tailored to this situation. For example, the Automatic Block Signal System operates under predefined conditions that may not adequately address the complexities of trains moving against traffic. Common signal operation rules refer to general guidelines that apply to various signaling situations, potentially lacking the specificity needed for trains operating in reverse traffic conditions. Steam locomotive guidelines focus solely on the operation of steam engines, which do not pertain directly to the signaling and operational practices necessary in the context of opposing traffic.