An operational delay that occurs when a train is forced to slow down or stop because the block signals ahead are not clear. This usually happens when following a slower train, approaching a congested interlocking, or dealing with a track circuit failure.
We lost twenty minutes to a signal check coming through the canyon because the local freight was out ahead of us.
Engineers often note signal checks on their delay reports to explain why they failed to make track speed.
Related terms
Block signal
A fixed trackside light or semaphore that tells an engineer whether the track segment ahead is clear.
Signal aspect
The visual appearance of a railway signal that conveys a specific rule to the crew.
Restricted speed
A speed slow enough to stop within half the distance you can see, used whenever the track ahead may be occupied.