Where a Ground Frame controls a turnout which is facing to the direction of normal travel, an additional lever is provided which locks the facing point in position until the facing point lock is reversed. This provides additional security and a check for the operator.
To reverse a facing point, the facing point lock must first be reversed. The facing point can then be moved reverse. The facing point lock must then be returned to the normal position which locks the facing point in position. The opposite happens to restore the facing point to the normal position.
Motor points on passenger lines will always have a facing point lock contained within the point machines. FPLs are mandatory on passenger lines for all facing moves in the UK since the nineteenth century. Detection will not be given on points fitted with an FPL unless it is engaged correctly.
Last edited by GeoffM on 15/09/2016 at 03:00