Product category:
Cabling, Conduit, Accessories and Signal Conditioning
News Release from: Nexans | Subject: Axle counter cables
Edited by the Engineeringtalk Editorial
Team on 06 June 2005
Novel cable meets track-side demands
A special design of signal cable promises the ideal combination of high performance, long life, reliability and compact installed dimensions for train axle counter systems.
Nexans has developed a special design of signal cable it reckons offers the ideal combination of high performance, long life, reliability and compact installed dimensions for train axle counter systems Axle counters are track-side devices that monitor and count the number of train wheels passing by them - replacing semaphore signals and supplementing traffic-light signals by providing real-time train position information direct from the track-side
This article was originally published on Engineeringtalk on 27 Sep 2005 at 8.00am (UK)
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The role of the Nexans signal cable is to connect the track-side axle counters, which are usually positioned at intervals of between 1 and 3km, to the central monitoring system.
Operating power is provided by a separate cable, although in a number of similar applications worldwide, such as for Balise systems, Nexans has extensive experience in supplying combined power and signal cables.
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Typically, the operating signals from the axle counters vary between 60 and 90V, and a key requirement for this very demanding safety-critical application is that the cable should offer a low voltage drop, with a loss of just a few volts over long lengths.
This is significantly better than conventional signal cables.
Furthermore, the cable also has to offer a high level of shielding against the electromagnetic interference (EMI) produced by high-voltage overhead catenaries and other power feeds.
In addition to the electrical characteristics, rail infrastructure companies require a fully watertight cable that can offer total reliability over a 20-year service life, as well as being able to resist extreme temperatures, oil and ultraviolet light.
At the same time the cable has to be compact in size and flexible enough to enable it to fit easily within the already crowded concrete cable ducts.
Nexans responded to this challenge by developing a new specification for axle counter cables, comprising low- and high-count twisted copper pairs, with a low-loss insulation, adapted to each application.
A particular problem for rail cables can be the risk of rodent attack, and there are cases where standard cables have failed in less than a month due to gnawing by rats.
Nexans has tackled this by adding an armoured layer for use in areas of risk.
Low smoke, halogen-free and fire retardant versions have also been developed for tunnel and station installations.
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