Fraunhofer Institute for Physical Measurement Techniques IPM
Fraunhofer Institute for Physical Measurement Techniques IPM
Wire Wear Measurement System
© Fraunhofer IPM
A camera combined with special LED lighting enables overhead rail lines to be measured.

Detecting wear of contact wire on time

Camera systems measure the wear of up to ten contact wires simultaneously – at travelling speeds of up to 350 km/h.

© Fraunhofer IPM

© Fraunhofer IPM

Sliding surface indicates wear

The degree of wear of contact wires with a round cross-section can be calculated from the width of their sliding surface and should not fall below the specified values.

© Fraunhofer IPM

Contact Wire Wear

Preventing catenary rupture

Most trains today run on electricity and are supplied with power by overhead line systems. While the train is in motion, the so-called pantograph permanently slides against the overhead line, mostly made of copper, with a certain contact pressure. In the long run, the overhead contact line wears out, threatening to break – with potentially fatal consequences. Therefore, overhead contact wires need to be replaced as soon as they have fallen below a specified thickness. Railway companies therefore check the contact wire thickness at regular intervals – if possible quickly and efficiently in regular operation.

Wire Wear Monitoring System WWS

The contact wire wear measuring system WWS, developed by Fraunhofer IPM, measures the degree of wear of up to ten contact wires – simultaneously and without touching them. The residual thickness of contact wires with a round profile is calculated from the width of their sliding surface. The camera-based WWS picks up the sliding mirror and at a speed of 100 km/h derives an indication of the degree of wear of the wires typically every 13 mm.

Due to its high measurement frequency and fast data processing, the system is suitable for speeds of up to 350 km/h. Thanks to an independent lighting unit, the WWS does not require daylight and is therefore also able to operate reliably at night, in tunnels or under bridges.

The entire overhead line in view

WWS is also part of the multi-sensor system CIS (Contact Wire Inspection System) and its low-speed variant CIS-LS. These systems record contact wire wear and contact wire position simultaneously and, optionally, identify the position of poles.

Further applications »Railway Measurement«