Search results
Results from the WOW.Com Content Network
The third-rail system of electrification is not related to the third rail used in dual-gauge railways. The system is generally associated with a low voltage (rarely above 750 V) and is far less used for main lines than overhead line that with an higher voltage permit more distance between the substations. Also, for safety reason, third rail ...
Modern European systems predominantly make use of bottom or side contact power rails. There are numerous urban rail systems, including these running mostly in tunnels, which do not use third rail at all. Such systems can be found in Asia, which may have been influenced by the overhead power supply formula followed by Tokyo Metro after 1960
Both overhead wire and third-rail systems usually use the running rails as the return conductor, but some systems use a separate fourth rail for this purpose. In comparison to the principal alternative, the diesel engine , electric railways offer substantially better energy efficiency , lower emissions , and lower operating costs.
Converted to 25 kV 50 Hz as a test bed for the future main line electrification system South London line: London Victoria to London Bridge: 1909–1928 Converted to 660 V (later 750 V) DC third-rail supply 8 kV: 25 Hz Germany: Karlsruhe: Alb Valley Railway: 1911–1966, today using 750 V DC 10 kV Netherlands: The Hague – Rotterdam: Hofpleinlijn
Railway electrification as a means of traction emerged at the end of the nineteenth century, although experiments in electric rail have been traced back to the mid-nineteenth century. [1] Thomas Davenport , in Brandon, Vermont , erected a circular model railroad on which ran battery-powered locomotives (or locomotives running on battery-powered ...
A 675 V DC third rail (Top Contact) system was used. [19] Electrification was later changed to 11 kV 25 Hz overhead catenary, when the PRR electrified its mainline to Washington, D. C. in the early 1930s. Third rail is still installed in the East River Tunnels in order to provide power the LIRR trains.
Traction current converter plants are either decentralized (where one plant directly supplies the overhead lines or third rail of the traction system, with no feed into a traction current distribution network) or centralized (for the supply of the traction power network, usually in addition to the direct supply of the overhead lines or third rail).
The contact shoe may slide on top of the third rail (top running), on the bottom (bottom running) or on the side (side running). The side running contact shoe is used against the guide bars on rubber-tired metros. A vertical contact shoe is used on fourth rail systems. A pair of contact shoes was used on underground current collection systems.