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Im1: Prototype 90 degree crank with equal length arms. This photo was taken at The Swanage Railway of a spare crank laid on a stack of old sleepers. The hole at the pivot point is larger than those at the outer ends of the arms, this is to allow a large diameter bearing pin to be used providing a very strong fixing point capable of withstanding relatively high loads. A signal arm or points and rodding covered in snow or partially frozen can require an incredible amount of force to free the mechanism, start and complete the movement. Modellers! For those of You modelling in larger scales bearings can also be fitted reducing the amount of friction acting on the pivot point, minimising the effort required to move the rodding run and reducing stresses throughout the length of rodding thus extending the operational life of the crank pivot in service. Take note of the rounded arm ends and "web" effect between the arms caused by the large pivot tube not being central to the flat metal "L". Also note that the pivot point is not a hole in a flat metal "L" shape, it is normally cast as an integral part of the crank but in model form could be easily and effectively emulated with a short length of pipe attached at 90 degrees to the flat crank plate.

Im2: Adjustable crank. One crank arm is longer than the other and is fitted with a sliding collar clamp, this collar is connected to the rod that controls the FPL (Facing Point Lock) mechanism. The collar can be moved along the crank arm to set the correct throw required for operation of the point lock mechanism and locked in place.

Im3: Compensators. These compensators have been fitted below the main rodding run. Note the short lengths of angled rod used to drop down below the rodding run level to the compensator cranks.

Im4: Prototype FPL at Swanage. All facing point connections that carry passenger services must be fitted with Facing Point Locks to ensure the points are locked in place before a train is signalled over the route. The points are also fitted with detector units to provide a positive indication that the point blades are set correctly and locked in position ready for traffic.

Im5: Prototype FPL at Swanage. In this case both points are facing the normal flow of passenger traffic and require FPL mechanisms and detectors to be fitted.

Im6: One of the ground frames at Swanage. The FPL mechanisms can be seen just behind the ground frame to the right, the two boxes beside the points to the right of the running rails are detectors required for electrical proving of the point blades position. This ground frame was removed a few days after this photo was taken having now been replaced by the new Swanage Signalbox. (Jan2003)