What should be done if there is no written specification for a yellow flag restriction?

When there is no written specification for a yellow flag restriction, the appropriate action is to reduce speed to not exceed 10 MPH. This safety protocol is crucial as yellow flags indicate a cautionary situation where conditions may not be clear, or there may be an obstruction on the track that requires extra vigilance.

Reducing speed allows the train crew to maintain control and react appropriately to any unforeseen circumstances that may arise. It provides the opportunity to assess the situation more clearly without the risks associated with traveling at higher speeds. This conservative approach ensures safety for the crew, the train, and any personnel or equipment that might be in proximity to the tracks.

The other responses do not prioritize safety in the same way. Continuing at normal speed could lead to accidents since the specifics of the restriction are unclear. Turning back immediately without understanding the situation could create additional hazards and confusion. Communicating with nearby trains, while important in many scenarios, does not directly address the need for immediate reduction in speed when a yellow flag is present without clear instructions. Therefore, the most responsible action is to reduce speed as specified.