What action is required when encountering sticking brakes on a train?

When encountering sticking brakes on a train, the appropriate and required action is to stop the train and investigate. This step is crucial for several reasons:

First, sticking brakes can indicate a malfunction or safety issue that could lead to more significant problems if left unchecked. Stopping the train allows the crew to assess the situation thoroughly and ensure that the train is safe to continue its journey.

Additionally, by stopping, the crew can perform necessary checks around the affected brakes to determine the nature of the problem, such as inspecting brake components or assessing whether there is a potential for overheating due to friction. This proactive approach helps maintain safety standards, protect the train's mechanical systems, and safeguard the passengers and crew on board.

Moving forward without addressing the sticking brakes, as some other options suggest, could exacerbate the issue or lead to a dangerous situation, such as an inability to stop the train effectively when needed. Therefore, halting the train for an investigation is essential for operational safety and compliance with regulations.