What indicates a loss of ED brake, and what should the driver do?

The situation described involves a loss of the emergency (ED) brake, which is a critical safety feature within a train's braking system. The correct indication of a loss of ED brake is typically indicated by the illumination of the yellow brake inhibit light. When this light is illuminated, it signifies that the emergency brake function is not available, meaning that it cannot be engaged.

In this scenario, the appropriate action for the driver is to take no immediate action concerning braking systems because the yellow brake inhibit light means the main braking systems are presumably still functional and the train can still be operated safely within the limits of its regular braking mechanisms. The driver should monitor the situation and ensure that the train is still compliant with operational protocols.

The other options indicate actions that are either unnecessary or may be counterproductive in response to the specific situation of the yellow brake inhibit light being on. Recognizing the proper indicator and understanding when to act helps ensure that the driver manages both operational safety and compliance effectively.