What speed should trains not exceed when water is above the top of the rail?

When water is above the top of the rail, it poses significant risks to train safety, including potential flooding of the tracks and reduced visibility for crew members. The recommended speed limit of 5 mph in such conditions is a precaution to ensure safe navigation through flooded areas.

This low speed allows for better control of the train and minimizes the risk of accidents that could arise from hydroplaning or unexpected track conditions caused by water. By maintaining a slower speed, the crew can react more effectively to any unforeseen circumstances that may arise in these hazardous situations. Other speeds may be deemed too fast for the safety of both the train and its passengers when faced with significant flooding on the tracks.