What is the Maximum Allowable Speed (MAS) for a push-pull train when speed control is cut out?

The correct answer is 30 MPH because this speed is established as the Maximum Allowable Speed (MAS) for push-pull trains when speed control systems are not in operation or have been cut out. This regulation is put in place to ensure safety and operational control under conditions where automatic speed control features, which typically aid in preventing excessive speeds, are unavailable.

By limiting the speed to 30 MPH under these circumstances, the guidelines aim to provide a buffer for train operators to maintain safe handling of the train. The specific speed also reflects considerations such as track conditions, train handling characteristics, and the need to be able to react to any unexpected situations while on the move.

Any higher speeds, as seen in the other options, would increase risks under the absence of automated control systems, which is why 30 MPH is chosen as the standard. This measure reflects a careful balance between operational efficiency and safety protocols.