What is a chain marker used for?

A chain marker serves an essential purpose in the context of railway operations by identifying the distance to key locations along the tracks. This can include vital markers for mileposts, points of interest, or any significant landmarks that help workers navigate and gauge their positioning in relation to the entire rail system. Knowing the distance to these points is crucial for worker safety and for the coordination of operations on the railway, as it allows for better planning and execution of work activities.

The other options do not accurately describe the function of a chain marker. For instance, arrival times of trains are typically communicated through different systems, such as timetables or signal systems, rather than being marked directly on the tracks. Weight limits are specified by other means, such as signage or regulations, not by markers. Similarly, while maintenance crews do use various signaling methods, the primary function of a chain marker is distance identification rather than signaling for inspections.