Oberleitung

Oberleitung, or overhead line, is an electrical power supply system for rail, tram, and trolleybus networks in which the conductors are mounted above the track. It provides the traction current that electric vehicles collect through a pantograph or, in some cases, a trolley pole. The system is designed to deliver high voltage with continuous contact while the vehicle moves along the line.

A typical Oberleitung system consists of an overhead contact wire that the vehicle contacts, a supporting structure of masts or poles with insulators, and a messenger or feeder wires that maintain tension and alignment. The contact wire is kept at a precise height and tension to ensure reliable contact across varying weather and speeds. The return path for current is generally provided through the rails and track grounding. Special equipment, such as feeders, substations, and sectionalizing devices, manages voltage regulation and power distribution along the route.

The configuration of Oberleitung varies by country and application. Common designs use a catenary arrangement with a single contact wire fed from one or more substations, sometimes supplemented by a second wire for redundancy or high-speed operation. Urban networks and high-speed rail systems may differ in wire arrangement, voltage, and frequency, reflecting national standards. Typical voltages include 750–1500 V DC for trams, 3 kV DC or 15 kV 16.7 Hz AC for many railways, and 25 kV 50 Hz AC for newer mainlines.

Maintenance and safety are critical aspects, as the system operates at high voltages and spans across and above public infrastructure. Regular inspection, tension adjustment, insulation checks, and weather-related performance assessments are essential to ensure continuous, safe traction power.