Revoke Overlap Route Button
An overlap route is a small route ahead of a train route that is set for safety purposes - if a train would pass a red signal, the overlap route provides an extra measure of safety. When revoking a train route, an overlap route sometimes needs to be revoked as well. Revoking an overlap route is done using the DHT button.
To revoke an overlap route press DHT together with the end signal button (from which the overlap route is set). When successful, the overlap route will disappear.