The use of ballast as a foundation for railway tracks has a long and successful history. And, as we find out, there are a number of good reasons for that.

Track components can be mass produced at low cost and, thanks to the excellent accessibility, track parts can be replaced or repaired easily. And last but not least, height differences and depressions can be evened out without major expenses and innovative track forms can be constructed without problems.
Nevertheless, ballast is also unquestionably the weakest link in the track system. One need merely think of the enormous forces exerted on the ballast beneath the sleepers, resulting in tremendous wear due to the low contact area between the bottom of the sleeper and the ballast itself.
This leads to wear and tear on the points and edges of the ballast, and the development of contact area is not consistent along the length of the track, which causes track irregularities. These distortions in the track can finally lead to a range of other problems, up to and including changes in track geometry.
Especially with the increase in speeds of modern trains, the braking forces bearing on the ballast are pushing this time-honoured solution to the limits of its physical capacity.
This is why the search for alternatives is on around the world, alternatives which meet the needs of the 21st century.
But much of what has hit the headlines as 'innovation' has been but a flash in the pan and never made it past being a just another 'bad compromise'.
Now, though, the solution to this riddle is in sight. The basic idea is to defuse the riskiest area - the contact surface between the sleeper and the ballast - using an elastic layer. Such an elastic layer deforms to match the ballast rocks, so that these embed in the elastomer pad. Not only does this relieve the extreme local pressures between the ballast and the bottom of the sleeper, it also evens out the elastic characteristics of each successive sleeper in the track.

Elastic sleeper pads

Higher speeds and higher axle loads require a softer track. And this is where Getzner Werkstoffe enters the picture, playing a leading role in solving this difficult technical challenge, by providing a new elastic polyurethane element: a high-performance sleeper pad.
In a nutshell: using this new method of connecting the sleeper to the elastic bearing layer, the drawbacks of ballasted superstructure discussed above are overcome, without having to forego any of ballast's traditional advantages.
Thanks to ground-breaking solutions and close cooperation with its partners from all walks of industry, Getzner-Werkstoffe has once again made a major step forward in providing safety and comfort for the railways of the 21st century.
And what is more, the slightly higher initial investment costs are quickly covered by the substantially lower regular maintenance costs.

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Getzner Werkstoffe GmbHis based in Burs/Bludenz, Austria. www.getzner.at/werkstoffe