SR is an abbreviation for Self Restored points. Five seconds after a route has been used, the points will automatically return to their normal position.
There are two main variations to this: one variety will only self-restore if a train passes over the points and unlocks the route; the other will restore after the time interval when any locking is removed.
Self resotring points are provided most often out of sidings or yards where there is a risk of a runaway train following a signalled train out of that yard or siding. By restoring the points after a signalled movement, the points return to their "safe" position, diverting any runaways to a safer place than a main line.
Last edited by GeoffM on 15/09/2016 at 03:00