TENSOREX – Spring Tensioning System for Overhead Lines on Electric Railways

Reliable compensation of temperature-linked changes to the length of the contact wire is a basic requirement for seamless operation on the railway. Conventional tensioning wheels are now being replaced by the cutting-edge TENSOREX C+ spring tensioning system by PFISTERER. The intelligent system impresses with its compact and maintenance-free design for regional and long-distance trains.

The most compact tensioning system on the market

TENSOREX C+ is an innovative tensioning system for overhead lines on electric railway systems and makes sure that the tensioned wires and cables remain at a constant height. The tensioning force required for this purpose is produced by the patented combination of a spiral spring and an eccentric disc, meaning that cement or cast steel weights are no longer needed. This reduces the amount of space needed and allows for easy installation in tunnels. If necessary, the TENSOREX C+ can be installed directly on the sides or ceiling of a tunnel and rotated by up to 90°.

Shorter installation processes – No maintenance required

The TENSOREX C+ is supplied ready for installation and can be mounted onto all forms of tower straight away. Following this, the contact wire and/or messenger wire can be fitted. The system is maintenance-free. Lubricating, oiling, and other complicated repair work – particularly positioning the weights on the tower – are now a thing of the past. Should one of the wires break, the entire system can be reused – all you have to do is fit the new wire. Furthermore, you can check the current settings at a glance at any time – complicated measurements are no more.

Innovation and tradition for ultimate reliability

PFISTERER produces and delivers the TENSOREX C+ for a wide range of tensioning forces and lengths. The tensioning method is based on the established TENSOREX system which has proven itself for over 15 years. After being significantly reduced in size yet again, the TENSOREX C+ is unique on the market and an important component in modern railway catenary systems.


  • Very compact, supplied ready for installation
  • Lower gross weight compared to tensioning systems that use weights
  • Maintenance-free – no need to keep spare parts to hand
  • High response accuracy
  • Can be used on all forms of tower and building
  • Moving parts remain out of reach
  • No need to install protective grids
  • No need to keep space free for weight structures
  • Can be recommissioned straight away following wire breakage


Haidian District, in the west of Beijing, has gained a new tram line. The Beijing Western Suburban Line links Bagou with Xiangshan Park. The overhead lines along the whole new route are tensioned with the innovative TENSOREX C+ spring-tensioning system.


Ankara to Istanbul in just three and a half hours? The new high-speed rail link using specialist technology by PFISTERER transports passengers to the global hub at high speed – even over tricky terrain.


The longest railway tunnel in the world has to remain accessible in any situation, even when repairing the tracks. The unobstructed and fully-accessible earthing and short-circuit devices by PFISTERER make this possible.


Ideal dimensions and a patented spring system make the TENSOREX C+ the winner of tests by the Austrian Railway Network. It makes sure wires and cables are perfectly tensioned no matter what the weather, even in narrow tunnels.