A marker is utilized to:

The use of a marker is specifically to show the end of a train. This is a crucial function in railway operations, as it ensures that other trains or railway personnel are aware of where the train ends. Markers are typically placed on the last car of a train, and they are designed to be easily visible, often reflecting light or using bright colors. This helps to prevent accidents by clearly indicating that there is more than just the locomotive, allowing for safe distances to be maintained by other trains approaching from behind. The visibility of the marker also aids in efficient train handling, ensuring proper communication about the train's length and location on the tracks.