Clear Board

Clear Board
A signal indication which authorizes a train to proceed.
Clear Crossing
A track clear system that signals when a roadway crossing is clear of a train.

Clear Board
A signal indication which authorizes a train to proceed.
Clerestory Roof
Raised center portion along the length of a roof of certain passenger cars featuring "clerestory windows" along the sides to allow natural light into the car.

Clear Board
A signal indication displayed to advise that no train orders are being held (also see Board).
Clearance or Clearance Limit ...

Clear Board - A go-ahead signal.
Clear Signal - Fixes signal displaying a green, or proceed without restriction..

clear board (for clear tracks) or red board (stop). Do not confuse this with extra board or spare board, colloquially known as slow board or starvation list, ...

Train standing in the signal block waiting for a clear board.
In The Ditch
Wrecked or derailed.

See also: Switch, Track, Section, Locomotive, Truck