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Article Date: 14th November 2014

PMA UK - Are your Cables Providing Tasty Treats for Vermin?

Cable Protection - Cable Management - Conduit Systems - Flexible Conduit


Throughout the years, there have been many stories in the media and on television about Rats causing chaos for railway lines. Back in 2010, millions of pounds had to be spent on the repair and replacement of 20,000 miles of rail track, across the UK, solely due to Rats gnawing and damaging cables.

Of course, with damage to this cabling comes serious implications to trains and their passengers; severe delays, break downs and, in some tragic cases, even crashes. July, 2014 saw a collision in South Western France between a high-speed TGV and Regional train leaving 40 passengers badly injured, all because of a signal malfunction created by Rat activity.

But why is cabling so important? Rail cabling holds vital data within it and is responsible for controlling the signalling infrastructure of its railways. Without - or through damage to - said cabling, trains simply cannot drive safely on their tracks; electrical short circuits, incorrect signals, miscommunications and/or fires could easily occur. Therefore, it's equally as vital to the safe, smooth running of trains on the track that this cabling is adequately protected against potential damage from a 'Rat Attack'!

In conjunction, to adequately protect against this potentially devastating issue, we have to understand exactly WHY Rats gnaw through and damage the cabling in the first place. There seem to be several reasons for these actions:

Firstly, Rats have open-rooted incisors and molars - meaning that their teeth never stop growing and as a result they have to incessantly gnaw hard materials to keep their teeth ground down.

Secondly, Wild Rats are natural foragers and will use anything they can find - including electrical cabling! - as nesting material.

Thirdly, and most commonly, Wild Rats are territorial creatures whom use urine as a way to mark territory. If and when they smell the urine of another Rat on their marked territory, they gnaw the affected material away; removing the offending Rat's scent.

As stated, it is the third point - the marking of territory - that is the main reason why Rats damage and gnaw this all-important cabling. Therefore, it is this issue that needs specific, urgent attention. But how?

Since Rodent gnawing and damage is such an important issue for railways, there are a number of products available that aim to prevent this. For example, a 'trunk' cabling solution made from corrugated steel sheath and a stainless-steel pipe. As a second example, a 'Brush' has been design which lays neatly over the cabling and across any vulnerable cavities, in efforts to stop Rats getting to the cables. However, if this 'Brush' were to become damaged itself, Rats may then be able to get to the cables and still gnaw away at them.

So, the question then becomes: what can we do to directly protect the cables themselves from this potentially devastating problem?

Polyamide is a polymer based around an amide linkage. Commonly known as 'Nylon', the term refers to a range of materials with similar properties; materials that are incredibly tough with great thermal and chemical resistance. This means that not only would polyamide materials be physically resistant to the strength of Rats' teeth, but also 'forget' (resist) the scent of their urine - removing the need for territorial gnawing away of other Rats' scents - and consequently making them perfect for rail cable protection.

After much research and thorough testing, PMA Cable Protection have developed a polyamide protection with the specific properties to stop Rodents gnawing and damaging the cables. With polyamide, the risk of Rodent damage is significantly reduced also because urine and other marking substances don't adhere to its smooth, shiny surface.

Along with this, polyamide helps prevent Rats from using the cabling as nesting material. This is due to the fact that polyamide is considered an unattractive 'building material', because of the amount of effort required to bite into it - with its hard and elastic properties teeth are inclined to slip and Rats quickly lose interest in trying to remove and use it. This also means that the larger the conduit, the more difficult it is for an animal to bite into its surface.

PMA's testing process ensures that polyamide materials help in the prevention of Rodent damage to rail cabling; with all of PMA's products being tested beyond industry standard, to destruction. Mark Fletcher, Thomas & Betts Rail Specialist, remarks:

"All our systems meet with Network Rail’s requirements on modular wiring... providing a range of [additional] benefits, such as being resistant to corrosion and rodents.”

With so many tracks deep underground - the London Underground and Glasgow Subway, for example - and near vast expanses of water, Rats will always be a regular pest on the railways. However, with polyamide cable protection, fear of damage from any type of Rodent can be irradicated.

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