A method of controlling train movements on a single line of track without requiring the engineer to pick up a physical staff or token. Instead, the system relies on track circuits and electrical interlocking between adjacent signal boxes to ensure only one train can enter the block at a time. This allows trains to pass through without slowing down to exchange physical objects.
Heard on the job
They upgraded the branch to tokenless block last fall to speed up the freight schedules.
Related terms
Block system
A method of safely spacing trains by dividing the track into segments and controlling entry to each.
Track circuit
A low-voltage electrical circuit running through the rails to detect the presence of a train.
Block section
A defined length of track governed by signals that only one train may occupy at a time.