Only after getting the contours of wheels and rail, and combining the two together, the effect of geometric contact conditions on the running performance of operating railway cars can be obtained.

只有掌握了车轮和轨道的轮廓型面，并将两者相结合，才可能掌握几何接触状况对铁路运营车辆的运行性能所产生的影响。

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Three firms are currently bidding for the chance to operate the service - one of which is Prism Rail who holds two of the franchises, Wales and West and the Cardiff Railway Company.

BBC: News Online