Clearing Points

Clearing points are an important concept in railway signalling, particularly for lever frames.

Definition: The clearing point, is the point to which the line must be clear, in order to accept a train.

  • The clearing point is usually a sufficient distance beyond the home signal to protect a train that overshoots the home signal.
  • Clearing points are usually specified in the local box instructions: if not specified, a rule of thumb is to allow 400 yds beyond the home signal.
  • To accept a train, the line must be clear to the home signal, in this context, clear means:
    • No other trains in the section up to and including the clearing point
    • No other routes signalled that enter, overlap, cross or conflict with the section up to the clearing point.
    • Points in the section up to the clearing point set, and locked if facing.
  • Once a train is accepted, the clearing distance must be maintained. This means:
    • No other train may be allowed into the section, or the clearing distance.
    • No other route may be signalled that enters, overlaps, crosses or conflicts with the section or the clearing distance.
    • Any points in the section of clearing distance must not be moved, and must remain locked if facing points.
  • These conditions must be maintained until the train has passed through the section -or- the train has been brought to a stand at a signal.