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Service upscale: long-welded rails containing expansion joints

13 October 2020 | 

Changing temperatures and their impact on rail structures make working in the tracks a challenging work place. So how can we raise the levels of safety and quality to even higher standards? By offering the use of long-welded rails connected to expansion joints. Our specialists at our Rail Service Centre (hereafter RSC) attach these joints to the long(er) rails by means of a flash butt weld procedure. The expansion joint is directly ready for use, and can be assembled a lot quicker, simpler, and safer. In addition, the method generates a considerable reduction in costs.

Expansion joints; what was the deal again?

It is common knowledge that steel expands at high temperatures and shrinks at low temperatures. The result during temperature changes is that rails either expand or shrink. Rails are not the only objects susceptible to ‘expansion’; (steel) bridges, for example, can extend or reduce in size as well. The forces ensuing from this process also have quite an impact on the rails. Usually, sleepers in combination with ballast are able to absorb these forces. However, in some cases, they are so strong that the rails are pushed outwards, causing so-called rail buckling (particularly in the rail curves). It is therefore crucial that there is sufficient room for the rails to dilate. In other words: to be able to move to some extent in a horizontal direction. This requirement is made possible by the ‘expansion weld’.

The expansion weld consists of two adapted rails positioned in such a manner, that they are able to expand or shrink independently without obstruction. As a result, neither of the two is burdened. Apart from their application on bridge structures, expansion joints are also regularly used at other locations within the railway system where large forces have an effect on the rail structure.

In collaboration with our railway partners, we developed the idea to execute the flash butt welding procedure for connecting long rails at our RSC. The ready-made rails can then be delivered at the construction side in the desired length of up to a maximum of 360 meters. The expansion joints with a maximum length of 36 meters can be transported on a truck. Longer lengths are also possible, however, these will be delivered on our Robel train.

Reduced risk

When using preassembled expansion joints, the risk of faults associated with the application of (thermite) welds is reduced. This means that, in case of outflow, the contractor will benefit from a considerable time advantage as well as cost reduction. In addition, the flash butt welds are made in our RSC under conditioned circumstances, which that benefit the quality and life span of the joints. In conclusion: a longer life cycle at lower costs.

Are you interested in long-welded rails containing expansion joints?

Take a look in our web shop to check out our assortment of expansion welds. Would you like to receive more information? Do not hesitate to contact our product manager Daniël Poll Jonker or our international sales department.