What should a locomotive engineer do if they encounter a signal showing "stop"?

When a locomotive engineer encounters a signal that indicates "stop," the appropriate action is to halt the train and follow established protocols. This is critical for ensuring safety on the railways. A "stop" signal is a clear directive that must be observed, as it indicates a potential hazard ahead that could involve other trains, obstacles, or work zones.

Following protocol means the engineer should assess the situation, communicate with dispatch if necessary, and wait for further instructions or for the signal to change. Adhering to this protocol is essential as it prevents accidents and ensures safe operations along the railway, maintaining the integrity of rail traffic and the safety of all personnel involved.

The other options present behaviors that would compromise safety, such as accelerating through the signal, waiting for instructions from passengers, or ignoring the signal, none of which are acceptable practices under railway safety standards.