What does a top red and small green marker light mean in a low speed signal?

A top red and small green marker light in a low-speed signal indicates that the train must move at a restricted speed to the next stop signal. This configuration, often referred to as a "restrictive signal," does not allow for full speed operation and requires the operator to proceed with caution.

The purpose of this signal aspect is to ensure that the train maintains a safe speed as it approaches the next signal, allowing the crew ample time to react to any further instructions or conditions on the track ahead. Adhering to such signals is crucial for maintaining safety protocols in railway operations, especially in situations where track conditions may require slower speeds for safety reasons or to safely navigate around other trains or obstacles.

This understanding is essential for railway workers, as it reinforces the importance of signal recognition and compliance to ensure safety in all aspects of train operations.