Rats and rail – Is your cable safe?

It's no surprise then, that rats have the run of the metro stations and sewers of our cities. But you will even find them in places with a reputation for their hygiene and cleanliness.
The most common species of rat in Europe and North America, is Rattus norvegicus. It goes by many names: the brown rat, sewer rat, wharf rat and street rat. Running cables through the tunnels, sewers and drains that they live in makes economic sense. But protecting this infrastructure from rodent damage is a real challenge. 

‘Don't underestimate the damage rodents and mustelids can cause on railway cables’

When Sylvie Herniou steps into her office in Paris on an average working day, rats, mice and mustelids – the family of mammals that includes martens, weasels, badgers and ferrets – are never far from her agenda.

“Don’t underestimate the damage rodents and mustelids can cause to railway cables,” she says. “The consequences can be life-threatening. And the amount of cable, including fibre optic, is increasing fast,” she adds. “Companies facing this problem soon realise that prevention is more cost-effective than repairs.”

“Our solution to this growing challenge is Twist-In RR. It's the ‘Rodent Repellent’ addition to our Helagaine range of protective woven sleeving: a physical layer of protection against gnawing teeth. That's a different approach to other products, which rely on chemicals. The problem with chemical repellents is that the effect may wear off over time. Renewing that costs repeated time, money and effort”, she explains. 
 

‘The problem with chemical repellents is that the effect may wear off over time’

The key to the reliability of Helagaine Twist-In RR lies in glass fibre filaments. These are woven into a robust, flexible polyester sleeve with self-closing properties. The material has good resistance to acids, solvents, UV, weathering and micro-organisms. Thus it is suitable for tough environments such as sewers, tunnels and rail infrastructure. "We designed Twist-In to be easy to retrofit around cables", adds Sylvie Herniou. "It self-wraps and is very flexible. That makes it more effective and practical than split-corrugated tubing."

“Rodents and mustelids adapt well to their environments”, Sylvie Herniou says. “The input of rodent experts was decisive in the development of our product: when rodents encounter a foreign urine mark in their territory, they try to obliterate it. If the mark is on cables, that’s when they are most likely to damage the insulation.” 

‘The input of rodent experts was decisive in the development of our product’

Helagaine Twist-In RR has been extensively tested. It’s also Sylvie Herniou’s job to work with laboratories, development partners and the end customers who are looking to protect their cable infrastructure.

The sleeving can be quickly installed without tools, making it suitable for large-scale networks. For example, a 15 km length of fibre optic cable of a French internet provider. “This company recognised the cost advantages of prevention with Twist-In RR. “But the problem of rodent damage is not confined to large-scale infrastructure. Many of us have also had to deal with martens or rats chewing hoses and wiring insulation on our vehicles. Exposed cabling in houses, offices, factories or farm buildings and machinery also need adequate protection.”

‘Helagaine Twist-In RR sleeving is a simple and effective way of preventing rodent damage.’

The risk of rodent damage in the rail sector is particularly high. France’s SNCF railway group has validated and adopted three sizes of Helagaine Twist-In RR sleeving. The catalyst was a train collision in southwest France in 2014. Forty passengers were injured, several seriously. The accident inquiry concluded two years later that rats had damaged cables, leading to signal failure and the regional train ploughing into the TGV at 95 km/h.

“Helagaine Twist-In RR sleeving is a simple and effective way of preventing that kind of rodent damage. It's a cost-effective way for rail operators to maintain network safety and efficiency”, Sylvie Herniou concludes. “The material is self-extinguishing and meets FMVSS 302 flammability requirements, is RoHS and ELV compliant (Article 4 - 2) and fulfils the HL3 requirements of R22/R23 according to EN45545-2.