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.

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