Rubber product : Rubber supported rails

In general, rails used to be supported by wooden sleepers. Wood was preferred because of its elasticity and its damping action. With modern permanent way, however, preference is given to reinforced concrete sleepers which facilitate the use of continuous welded rails. Their use eliminates rail joints and reduces the maintenance expenses due to joint ends, fishplates and securing bolts. However, the concrete sleepers are rather inelastic and because of this use is made of rubber sheet rail mats of special design and characteristic. These are mats with trapeze shaped grooves provided at the top and bottom faces to ensure the required compressive and shear elasticity. Because of the wide temperature variation, which on European railways can rang from 243 to 333 K (-30 to 60 *C), use has to be made of synthetic rubber. The mats are made in two size, 166x123x4.5 mm and 141x125x4.5 mm. The end are flanged to prevent displacement. The Geman Federal Railways(DB) have successfully applied these pad and also at high speeds. Similar pads are also used experimentally by the French State Railways and the Stockholm Underground.