25,863. British Thomson-Houston Co., [General Electric Co.]. Nov. 15. Electric traction on the overheadconductor or third-rail system. Collectors. -Relates to collecting- devices, more especially of the type described in Specification No. 401, A.D. 1905, and consists in means for retracting or advancing the collector, either automatically or manually, at desired points along the line of travel. Fig. 1 shows one form of collector and the necessary valves and connexions for simultaneously controlling two such collectors. The shoe or skate is supported on hinged levers 4, 5, and is pressed into engagement with the conductor by the springs 7. Another spring 17, which may be dispensed with, tends to keep the collector out of engagement, but is normally counteracted by fluid pressure supplied through the pipe 19. The levers 5 are fulcrumed on the pedestal 6 and have at their inner ends intermeshing gears, whereby they are caused to move in unison. The shoe is electrically connected by the flexible conductors 9 with the pedestal 6. The upper end of the piston-rod 15 is connected through the cross-head 13 and links 12 to the cranks 8, to which one end of the springs 7 are secured. When the piston falls, the tension of the springs is reduced and the skate is retracted. The cylinder 18 is connected by the pipe 19 with the controlling-valves 2, which are connected by the pipes 21 with a source of compressed air, and have exhaust ports 22 normally closed by slide valves 23. Each slide valve is operated by a double-ended piston 24, which is left unpacked so that the coinpressed air supplied through the pipe 21 may establish balanced pressures on its ends. The piston is moved to the left or right, to allow air to pass to the cylinder 18 through port 20 and to raise the piston 17, or to escape therefrom through ports 20, 22, by permitting air to escape from the corresponding end of the valve chamber. This can be done manually by the hand-lever 25 which controls the tappet valves 26, or automatically by the collector arms acting on the pilot valves 27, 28. The pilot valves are provided with spring-pressed levers 34, 35, which engage at their lower ends with the stems of the valves, and at their upper ends with projections 36, 37 carried by the collector arms 5. The lever 34 and projection 36 are so disposed as to operate the valve 27 to retract the collector whenever the collector moves above a predetermined level, the valve 28 being similarly operated, to raise the collector into its running position, when the collector is forced below its normal position. The air-pipes, connect with both collectors and controlling-valves, so that both collectors can be simultaneously operated from each valve. A double check valve 38 is arranged in the pipe 19 to prevent air from exhausting from one valve through the other. Fig. 2 shows a modified arrangement in which only one pilot valve is used, the collector being retracted whenever the shoe moves abnormally in either direction. The valve lever is provided with two operating-arms 51, 52 adapted to engage with the lug 53 and the upper part of the arm 5 respectively. Fig. 3 shows a slightly modified form of controlling-valve for use with the collector shown in Fig. 2. The pilot valve is connected up to the casing at 48 and the pipe 19 at 45, the orifice 45 being in communication with the port 20 in the slide-valve seat. The supply pipe and the manually-operated tappet valves are not shown in the drawing. The piston of the controlling-valve may be single-ended.