What is the purpose of a marker on a train?

A marker on a train serves an important function in conveying critical information about the train's configuration. Specifically, the purpose of a marker is to show that the train is complete. This means that the marker can provide visual confirmation to other train operators and personnel that all cars are coupled and that the train is ready for movement.

Markers are especially essential in ensuring safety and preventing accidents. For instance, if a train is missing any cars, it could pose a danger if other trains or personnel do not realize it. Therefore, displaying a marker helps to communicate the train's integrity to all involved in railway operations.

In contrast, while indicating a route, signaling a stop, or showing the weight of the train are important aspects of train operations, these functions are typically managed through different systems or signals and are not the primary purpose of a marker. Thus, the use of a marker directly relates to the train's completeness and readiness for operation.