An overhead contact line is a line system for supplying vehicles with electrical energy ( traction current ). Strictly speaking, this also includes the return line, for example via rails, feed and return cables. Contact lines for railways ( railway , subway , light rail , tram ) can be designed as an overhead line above the track or next to and / or in the track as a conductor rail . In halls, workshops or tunnels, an overhead conductor rail can also be installed instead of the overhead contact line.
Trams and light rail vehicles are usually supplied with electricity via an overhead line. For aesthetic reasons previously and again today - especially in inner cities - and between the rails laid Headed used for. B. on the Bordeaux tram .
Trolleybuses use overhead lines, which consist of an overhead contact line with two contact wires laid over the lane . Individual railways such as the Jungfrau Railway also use overhead lines with two contact wires, for example to enable a three-pole power supply for three-phase motors with the rails as the third pole ; In mainline railways , this principle has not proven itself due to the overly complicated contact wire arrangements in the area of railway switches . In order to guarantee a complete traction current supply in turnouts, it is necessary under two-pole three-phase contact lines to bridge the interruptions on turnouts with two pairs of pantographs (front and rear on the locomotive). Adequate safety distances must be maintained for overhead lines that are operated with high voltage . See overhead line: Safety, Accidents .
Completely independently run subways in large cities (in Germany in Berlin , Hamburg , Munich and Nuremberg ) have a laterally arranged power rail for reasons of clearance profile , which must be interrupted at switches and crossings . The oldest system in Germany, the small-profile subway in Berlin (lines U1 to U4), uses busbars that are coated from above, while the other systems use busbars that are coated from below. Such also uses the S-Bahn Berlin , the S-Bahn Hamburg contrast side coated has busbars. The London Underground uses both a side track and a track in the middle of the track, both of which are painted from above.
- Friedrich Kießling, Rainer Puschmann, Axel Schmieder: Contact Lines for Electrical Railways. Planning, design, implementation . Publicis Corporate Publishing, 2001, ISBN 3-89578-152-5
- Kießling, Puschmann, Schmieder: Contact lines for electric railways - planning, calculation, execution . Teubner, 2nd edition, Stuttgart 1998, ISBN 351916177X (old out of print edition in German)