What does the ADCL light indicate on PA5 cars?

The ADCL light on PA5 cars serves as an indication specifically related to the features or systems in use, particularly for a category of vehicles that includes both PA4 and PA5. The function of the ADCL light is designed to communicate important operational information to the engineer, especially relevant to the configuration differences or enhancements present in the PA5 model compared to earlier versions like the PA4.

The presence of the ADCL light signifies that it is primarily aimed at conveying diagnostics or operational alerts necessary for the engineer’s awareness, distinctly focusing on the functionality and status of the train's systems. This helps in managing and monitoring the various aspects of train operation, ensuring safety and efficiency.

The other choices relate to warnings or operational statuses that are specific to particular conditions such as low fuel, maintenance needs, or issues with brake wear. These do not accurately represent the primary purpose of the ADCL light, which is solely focused on the engineer's operational awareness on the PA4 and PA5 models.