Which term stands for the Maximum Authorized Speed (MAS), normally not exceeding 30 mph but up to 40 mph under cab signals in ASC territory?

• A. Limited Speed
• B. Maximum Authorized Speed (MAS)
• C. Medium Speed
• D. Restricted Speed

Answer: (B)

This question is about the official term for the speed you’re allowed to run under signal authority. The term stands for Maximum Authorized Speed, the maximum speed a train is officially permitted to operate at based on the signaling system. In ASC territory with cab signals, you can be cleared up to 40 mph if the cab signal indicates clearance; otherwise the MAS is typically limited to a lower value such as 30 mph. This is different from other speed terms that describe lower or conditional limits (like speeds for restricted conditions or yard operations), because MAS specifically denotes the maximum speed authorized by the signal system.