Flame-retardant and fail-safe igus solutions for the railway industry

06 Apr 2020

The number of passengers on public transport has been increasing steadily for 20 years. This is confirmed by figures from the Association of German Transport Companies.

This is good news for the industry, but also an increasing load on the rail network, trains, trams and equipment. Durable components are required that can withstand such high requirements and yet meet stringent fire safety standards. But how about reducing maintenance effort and costs with these components or dispensing with regular lubrication?

These components called motion plastics are developed and manufactured by igus. They simplify a variety of applications in trams and trains where things are in motion. Numerous igus products meet Hazard Level 3 according to DIN EN 45545. This includes plain bearings made from high-performance polymers and durable cables. Special plain bearing materials meet the R22/R23 test requirement, and
certain cables fulfil R15/R16. Another benefit of using motion plastics is to save weight because heavy metals are replaced by lightweight and long-lasting polymer components. Due to their special material properties, they are resistant to dirt, heat, cold, moisture and road salt. That's why they are used inside and outside in rail-bound traffic and transport.

When boarding a tram or train, passengers encounter the first igus components. chainflex cables, dryspin lead screw technology and energy supply systems are used to make door systems maintenance- free and, above all, reliable. Defective doors can constitute a hazard to passengers in emergency situations and, in everyday life, are hindrance to speedy passenger boarding and alighting. In order to ensure optimum cable protection despite the non-stop opening and closing of the doors, easy-to-install E2 micro e-chains from igus are used. Thanks to the modular system they can be adapted to the application and are suitable for the smallest installation spaces. A special design of the cable supply systems allows very lightweight and low-noise movements. The e-chain in combination with chainflex cables is a very robust combination. The chainflex cables have a 36-month guarantee and are designed for the smallest bend radii. Perfect for the small installation space in trams and trains. The dryspin lead screw systems are used to open and close doors. Their self-lubricating high-performance polymer lead screw nuts eliminate the need for an extra lubrication, reducing maintenance and cleaning costs. The drive for the lead screw systems can be igus DC motors or stepper motors. E2-micro e-chains, chainflex cables and dryspin lead screw systems are also used in the sliding step under the door because they can be used without any problem in dirt, road salt and rain.

Verkehrs-Aktiengesellschaft Nürnberg (VAG) is already profiting from the use of motion plastics and igus cables in the entrance systems of its trams. Each door of VAG railways has to cope with around 70,000 opening and closing cycles per year. Large, easy-to-install bolts in the e-chain used make it very stable while smooth contours reduce wear and tear on the cables. This is particularly important in the VAG's case, where very thin energy chains led to cable and chain damage in the past. In addition, CFSPECIAL.414 cables are used. They extend the maintenance intervals up to 16 years, as could be verified through tests. The CFSPECIAL.414 was specially developed for moving applications on railway vehicles and therefore has a halogen-free and flame-retardant jacket material.

Maintenance-free and clean applications in the passenger compartment

iglidur polymer plain bearings and drylin linear guides ensure clean adjustment, low coefficients of friction and quiet movement without the need for any additional lubrication. This is due to the incorporated dry lubricants, which are within the igus materials. That is why igus plain bearings and linear technology are used where cleanliness and high comfort are a must: in the passenger compartment. For example, adjustable armrests, folding tables and seats can be implemented using iglidur G. These plain bearings are wear-resistant and available, from stock, in a wide range of shapes and sizes. If the components have to be in line with DIN 45545, iglidur RW370 can be used. drylin linear guides also make folding tables extendable. Dirt and liquids do not make a difference to both iglidur plain bearings and drylin linear technology. Should anything be spilled or become dirty, the bearings of both products can be easily cleaned.


Linear technology for curved toilet doors

Defective toilet doors are a nuisance to passengers and operators. The drylin W linear guides are therefore used to guide curved toilet doors reliably and fail-safe. The bend radius can be freely selected with these linear guides and thus allows more design freedom. Thanks to drylin, maintenance is reduced to a minimum and the quiet opening and closing of the door guarantees maximum comfort for passengers. By dispensing with additional lubricants drylin contributes to hygiene and cleanliness. As additional lubricant is not needed, dirt and dust cannot stick. Due to the corrosion-free shafts and sliding carriages made of iglidur polymers, moisture is no problem in use. Often the doors run on iglidur plastic rollers, which are much more resistant to wear than comparable products made of POM or PA. The material is very robust so that the igus rollers do not flatten over time. In addition, they easily withstand shocks and vibrations.


Easily turn first class seats in the direction of travel

igus high-performance polymers ensure a comfortable sitting experience even in first class. With iglidur PRT slewing ring bearings, the seats can be turned in the direction of travel. Manually or even electrically. iglidur J sliding elements also make igus slewing ring bearings maintenance-free and remove the need for lubrication. The slewing ring bearings are available in various installation sizes. In order to make the travel experience perfect, drylin linear technology ensures headrests and footrests that can be easily and very quietly adjusted, as well as backrests and armrests. Depending on your requirements, linear guides can be used with or without locking function.


Insulating high-performance polymers in pantographs

As igubal spherical bearings are made of non-conductive high-performance polymers, they can be used as insulating components on pantographs. The igubal rod ends KBRM and KARM are used. The same non-conductive specifications are provided on pantographs by iglidur plain bearings, which are made of the materials G, H370, J, W300, X and Z. Each of these materials has certain advantages, such as conductivity, low moisture absorption or resistance to high temperatures. In this application both igus products display their maintenance-free use without corrosion.


The motion plastics are in use everywhere, from the driver's cab to the braking system

The properties of motion plastics also benefit the control elements of the train. For example, drylin linear guides are installed in the brake levers. For high wear resistance, bearings in control panels and emergency brakes are equipped with iglidur G plain bearings. iglidur plain bearings are also installed in brakes, because they allow trouble-free operation in the event of bumps. They are also corrosion-free and are unaffected by dirt. Use within wide temperature ranges between -100°C and 250°C are made possible by special materials that have been developed for extreme temperatures. Couplings also profit from the high reliability of iglidur plain bearings and thrust washers. In Scharfenberg couplings, for example, they are used in the main pin so that the hooked plate can turn during coupling.


Make the rail network weather-resistant with motion plastics

igus products are not just used on trains and trams. Their specifications are also in demand on track-side equipment and provide decisive advantages. The iglidur J plain bearings are installed in wheel tensioners and hinged cantilevers. In the wheel tensioners they are located in the wheel itself and ensure good adjustability despite the high load. In shunting switches, iglidur plain bearings are used to mount the rollers in the roller switching system. Here high-performance polymer plain bearings offer several benefits: they do not corrode and protect the shaft against wear. Since the plain bearings are temperature resistant, they can also withstand extreme weather conditions.


Robust cable guidance for maintenance halls and workshops

In maintenance halls and workshops, energy supply systems from igus are used in order to guide cables safely and increase their service life. Mechan Ltd., based in the UK, guides cables with igus e-chains on a traverser. This ensures that locomotives and wagons are quickly positioned on the right track. Up to 170 tons are pushed over a distance of up to 30 metres. To guide the cables safely and reliably, from the control unit to the traverser, even in the extreme weather conditions and harsh environments, and to keep the maintenance time to the minimum, the operators opted for an igus flizz system. This is made of stainless steel in which an E4 series e-chain and chainflex cables are used.