Keeping the trains on time

The only pleasure gained from a recent journey on an overcrowded, late-running train in Germany was discovering that a unexpected heavy snowfall resulted in exactly the same kind of chaos as we experience here. Problems come in several flavours. Ice on conductor rails prevents electricity finding a good path to the motors of electric trains using third rail systems. Ice, leaves or anything else on running rails can cause loss of adhesion on a hill. This can also affect track signalling systems that tell controllers where trains are, as well as failing to trigger signals to warn closely following trains or closing level crossing gates. During the recent Railtex show, Gérard Nisslé, export manager of French company Brot Technologies, told us at that within SNCF: "If there are leaves on the rails, the control room loses the signal for 30 seconds or a minute. This makes them crazy about whether to open or close the crossing gates." The Challenge Our challenge this month is to come up with the best possible method for dealing with ice and leaves on rails, whether providing electricity or adhesion or track signalling for the wheels. If you had an army of labourers available, as in early Victorian England, one could expect them to clean rails manually. The real Victorian solution was to provide locomotives with boxes of sand and trickle it onto the track in front of driving wheels, a technique still in use. When third-rail electric trains started to be used, the most successful technique to keep things going was to keep trains running back and forth through the night. At least one company at Railtex was promoting the use of large amounts of chemicals – de-icing on a grand scale – with unknown effects on the environment. The solution offered solves the problem elegantly and at remarkably low cost without using any kind of electronics. One element of the UK rail system has been using it for some time, but it has taken a while for other elements to embrace it. Once you see it, you will probably consider it obvious. For those without access to the web, the solution will be described fully in our May issue. There are also other solutions which some of readers may be aware of. Feel free to suggest your own ideas. Solution to Coffee-time Challenge The solution to this month's challenge comes from Davis Pneumatic Systems based in Plymouth. John Taylor, the company's sales manager told us that their 'Sleet Brushes' have been in use on London Underground trains working above ground since the early 1990s. The same devices are also fitted to Network Rail Multi Purpose Vehicles, more of which will go into general service later this year. The devices consist of a series of metal tines, inclined at 45 degrees to the direction of travel. The tines are made of softer steel than rails so while they will remove accumulations of sleet, snow and leaves, they will not wear rails. A pneumatic system presses them down against the rails when the driver presses a button in the cab. When there is no air pressure, they are withdrawn by a return spring. They are mounted on compliant rubber bushes. In the UK, they are used to clean conductor rails, but in France, they are to be fitted in front of running wheels in order to maintain the integrity of the track signalling circuit. Gérard Nisslé, export manager of the French company, Brot Technologies told us, "SNCF is very pleased with the results of the tests and they are seriously considering using this system instead of the existing one". TS More information from Davis Pneumatic Systems