What should be done if a train approaches a blue flag?

When a train approaches a blue flag, the appropriate action is to not pass the blue flag or a blue lamp. This protocol is essential for ensuring the safety of maintenance personnel who may be working on or near the tracks. Blue flags or lamps indicate that the area is potentially unsafe for train movement, and trains are required to stop and not proceed until the flag or lamp is removed. This rule is crucial in preventing accidents and protecting workers by clearly signaling that the area is occupied or hazardous.

The other responses do not uphold safety standards. Continuing at full speed disregards the warning, which poses serious risks. Notifying passengers to evacuate is unnecessary since the focus should be on stopping the train. Slowing down but continuing to move does not comply with the rules for blue flags, as it can still endanger the personnel in the area. Hence, the only safe and correct action is to stop and not proceed past the flag or lamp.