Contact Shoe Collectors Working Of Contact Shoe Collector Bow Collector system Construction of Bow Collector system Working of Bow Collector system žProperly the bow collector should be mounted in such a way so that the top edge of the collector plate would rise several inches above the wire when the collector frame is standing straight up. Thus the collector usually leans opposite to the direction of travel; when the time comes to travel in the opposite direction, the collector must be swung over. To allow this to happen, the overhead wire must be raised by several inches at places where the bows are swung over, such as terminals and turn-outs. This operation is usually achieved by ropes and pulleys. The collector is folded down to a horizontal position when the car is not in use. Advantages of Bow Collector system žThe bow collector has fewer moving parts than the trolley pole, but is heavier and sometimes more complicated to construct. The construction of overhead wires for bow collectors is simpler than trolley pole wiring. As bow collectors do not have revolving mountings, the collector cannot jump off the wire or follow the wrong one at intersections, as trolley poles sometimes do. Thus overhead 'frogs' and guides for trolley poles are not necessary with bow collectors. Bow collectors are, however, much noisier than trolley poles Old Age Pantograph Modern Pantograph Modern Pantograph žThe electric transmission system for modern electric rail systems consists of an upper weight carrying wire ( known as a catenary ) from which is suspended a contact wire. The pantograph is spring-loaded and pushes a contact shoe up against the contact wire to draw the electricity needed to run the train. The steel rails on the tracks act as the electrical return. As the train moves, the contact shoe slides along the wire and can set up acoustical standing waves in the wires which break the contact and degrade current collection. This means that on some systems adjacent pantographs are not permitted. Types of pantograph Single arm pantograph Double arm pantograph Single and double arm pantographs žPantographs may have either a single or a double arm. Double-arm pantographs are usually heavier, requiring more power to raise and lower, but may also be more fault-tolerant. žOn railways of the former USSR, the most widely-used pantographs are those with a double arm ("made of two rhombs"), but since the late 1990s there have been some single-arm pantographs on Russian railways ž Thank You By Chetan K. Bhavsar
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