What does a yellow lantern placed between the rails indicate?

A yellow lantern placed between the rails indicates a specific signal that requires the train to stop. This signal is crucial for ensuring the safety of operations, particularly when there may be workers present on or near the track or other safety-related issues that require immediate attention. Observing this signal means that train operators must halt their movement to assess the situation ahead or follow further instructions from the appropriate personnel.

In contrast, the other options refer to different situations and operational signals which a yellow lantern does not represent. For example, bringing a train under control in order to blow a warning might involve other signals or indicators but does not specifically relate to the meaning of a yellow lantern. Likewise, resuming normal operations or proceeding cautiously to a flagman would be indicated by other visual signals or conditions based on the fixed signaling system in place. Thus, the correct understanding of the yellow lantern's implications is critical for maintaining safety and operational integrity on the railway.