9936. Cosserat, W. A. P., O'Donnell, J. P., and Irving, E. C. May 1. Controlling and locking signals; indicators, point or switch and signal.-Relates to locking and indicating devices for use in apparatus for operating and controlling railway points, signals, crossing- gates, and the like, and consists of improvements in the systems and apparatus described in Specifications No. 183, A.D. 1900, No. 5575, A.D. 1901, and No. 2890, A.D. 1903. Fig. 1 shows a diagrammatic view of the device applied to a pneumatic system of operating railway switch points and signals as described in the abovementioned Specifications. L<1> is the hand operating- lever, X the compressed-air supply, V<10> the valve controlling the compressed-air supply which is operated by the lever L', C the cylinder, the piston of which is operated by the compressed air and reciprocates the plate M which moves the switch points S over as desired, and D the indicating-valve. The locking and indicating arrangement consists of notches or recesses in the lever L', in which engage rollers i<1>, i<2> on the piston-rods of pistons i<1O>, i<20>. Assuming the parts to be in the position shown, to operate the switch points, the signalman pulls over the lever L', thereby operating the valve V<10> and causing the roller i<1> to drop on to the horizontal part l<2> of the slot, and the roller i<2> to abut against the shoulder l<02>. Simultaneously, compressed air passes from the source X to the pipe o', lifting the diaphragm of valve R<30> and thus putting the cylinder C in communication with the supply pipe X<1>. The switches are then forced over and the valve D opened, thus permitting compressed air to pass to the cylinder P. The roller i<2> is then forced up the slot l<21>, completing the stroke of the lever L' and thus indicating that the points have moved over. Should any leakage of compressed air occur through the valve R<200>, the roller i<1> is forced into the locking-notch 1 and thus prevents any movement of the lever L'. In the modification shown in Fig. 2, when the lever is pulled over, compressed air also passes along a branch pipe 4, blowing over the plug valve 2, which closes indication pipe j, and moving roller i<1> upwards against the part 6. When the points have been operated, the indication current from the pipe k presses the roller i<2> into the slot l<21>, completing the movement of the lever L' and allowing the roller i<1> to lock the lever by passing into the slot 1. Fig. 3 shows a modification of the form shown in Fig. 2. Should any obstruction get into the points, the operator can release them sufficiently to take the obstruction out, but he is then compelled, through the action of the projection l<25>, to complete the original movement of the lever L'. Fig. 4 shows a modification which is more particularly applicable to a two-pipe system, and, like the form shown in Fig. 3, compels the completion of the original movement of the lever. In any of the arrangements shown, should there be a leakage of compressed air into the indication cylinders, the lever will become locked.