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The pantograph was an improvement on the simple trolley pole, which prevailed up to that time, primarily because the pantograph allows an electric-rail vehicle to travel at much higher speeds without losing contact with the overhead lines, e.g. due to dewirement of the trolley pole. Notwithstanding this, trolley pole current collection was used ...
Pantograph(left) and trolley pole in use on Queens Quay West, Toronto. All trolleybuses use trolley poles, and thus trolley poles remain in use worldwide, wherever trolleybuses are in operation (some 315 cities as of 2011), [7] and several manufacturers continue to make them, including Kiepe, Škoda and Lekov.
On curves, the "straight" wire between the supports causes the contact point to cross over the surface of the pantograph as the train travels around the curve. The movement of the contact wire across the head of the pantograph is called the "sweep". The zigzagging of the overhead line is not required for trolley poles.
The most common device is the pantograph, while some older systems use trolley poles or bow collectors. Ground-level power supply has become a more recent innovation. Another technology uses supercapacitors ; when an insulator at a track switch cuts off power from the tram for a short distance along the line, the tram can use energy stored in a ...
A trolleybus (also known as trolley bus, trolley coach, trackless trolley, trackless tram – in the 1910s and 1920s [1] – or trolley [2] [3]) is an electric bus that draws power from dual overhead wires (generally suspended from roadside posts) using spring-loaded trolley poles. Two wires, and two trolley poles, are required to complete the ...
Bow collectors are, however, much noisier than trolley poles. The overhead wires for bow collectors are stretched tighter than for trolley poles, and straight sections are 'staggered', that is, the wire does not run completely straight down the centreline of the track, but rather zig-zags slightly across a small distance.
In Italy this was achieved with the long bow collectors reaching right to the ends of the locomotive, or with a pair of pantographs, also mounted as far apart as possible. [13] In the United States, a pair of trolley poles were used. They worked well with a maximum speed of 15 miles per hour (24 km/h).
The cars are similar to those on the Media–Sharon Hill Line 100 series, SEPTA's suburban trolley routes, which were delivered around the same time. However, the subway–surface cars are single-ended and use trolley poles, while the suburban lines use double ended cars and pantographs for power collection.