While operating a westbound train, what is required if the HTD displays a VALVFAIL message?

The requirement to not exceed 30 MPH until the failure is corrected stems from the safety protocols and procedures designed to mitigate risks associated with train operations. When the Head-End Train Data (HTD) system displays a VALVFAIL message, it indicates a malfunction in the automatic braking system, specifically related to the integrity and functionality of the air brake valves. This malfunction poses a safety concern as it could lead to a failure in the braking system, which is crucial for controlling the train's speed and ensuring safe operation.

By limiting the train's speed to 30 MPH, it provides the crew with a manageable rate of operation that allows for better control and the ability to respond to any emergencies or further issues that may arise from the failure. This speed restriction is a precautionary measure to ensure that even in the event of an additional failure, the train can be managed safely without posing a risk to the crew, passengers, or infrastructure. The focus is on maintaining safety while en route to addressing the mechanical issue.

Other answers reflect actions that may be part of a broader response process but do not specifically address the immediate operational requirement regarding speed in this scenario.