In historic manual block and train order operations, this written form gave a crew the explicit authority to leave a siding or pass a red board. It served as physical proof that the dispatcher or operator had secured the route ahead. Crews were required to hold this physical paper before throttling up, ensuring no two trains occupied the same single-track section.
Heard on the job
We're stuck in the hole at milepost 42 waiting for the operator to hand up the release.
Also heard as
- clearance card
- release form