Computers on the line

Computers on the line

Driver’s cab, passenger monitors, train-land communication interfaces or automatic door control: these are just a few examples of on-board systems in trains that need to communicate with each other to ensure smooth train operations. As a result, modern trains are becoming more and more high-performance computers on wheels, whose most important lifelines – the connecting cables between the individual electronic components and signalling devices – must pass through sharp edges and narrow transitions.  

“If the cables are damaged, for example by continuous abrasion, short circuits can occur, which in the worst case can paralyse a critical system such as the brakes or cause a fire, “ explains Meike Kurzak, Managing Partner of DTi GmbH. “But data loss or faulty signal control can also occur because of abrasion damage. In addition, these cables are laid in very confined spaces with very little play and are also sometimes subject to high vibration or temperature fluctuations. For this reason, the edges need to be passed through equipped with a special edge protection, which previously had to be applied with the use of adhesives in a time-consuming process. Especially in case of fire, the nylon grommets themselves which when combined with the adhesives can cause an increased toxic load and smoke development. 

For this reason, an edge protection consisting of a particularly hard-wearing, non-flammable and steel-reinforced special thermoplastic, so that in the event of a fire it does not burn further or produce additional toxic smoke has been developed with a material which cannot dry out or become porous, even if it is exposed to extreme changes and temperatures. 

Minimising potential hazards

The special composition of SL-FST from Idviutech makes it very resistant to these extreme temperature fluctuations. As a result, the edge protector can be attached to the train both inside and outside. Even the high vibrations occurring on high-speed lines can be absorbed by the special construction of a securely fitting steel core and resistant plastic. 

DTi’s engineers have used their experience from aviation to develop the SL-FST, as the material has to perform under extreme speeds, G-forces and vibration environments in aircraft. “As more and more high-speed lines are being laid for trains in Europe, this synergy was a logical step in the development process,” Kurzak reports.

In particular, the performance of the material in contact with fire was a key factor in its adaptation to the European railway sector: “As many sections of track run through tunnels, fire safety requirements are particularly high in Europe,” explains Kurzak. “We have therefore optimised the plastic so that in terms of flammability and toxicity it does not add to the smoke and fire development, as would be the case with a plastic that contains questionable additives or is attached with adhesives.” 

“In practice this means that in a fire the SL-FST will not support combustion, burn insignificantly, and will only produce a very small, insignificant amount of smoke. As a result, the material meets the strict requirements of DIN EN 45545-2 and is qualified for Hazard Levels 2 and 3, which are the highest material-technical requirements within the framework of this DIN.”

The SL-FST castles lock automatically and provide strong edge retention. Nevertheless, the protection can be easily removed again. Since no adhesives are used, workers are no longer exposed to toxic chemicals (VOCs) and odours and do not have to wear gloves or masks when attaching the edge protection. “Adhesives and other solvents must be specially stored and disposed of and must be identified there by warning notices. Since the SL-FST installs completely without this, it is much more pleasant to work with and at the same time it becomes a very green alternative to what is being used now,” concludes Kurzak.