The previous track is seamed, there is no gap, is how to achieve
Seamless rail not thousands of kilometers without gaps, but the 25 meter long rail welding up into hundreds of metres long or even thousands of meters long, and then in the shop on the embankment, or the gap between 11 mm and a section of a seamless rail, now Shanghai Nanjing line is 303 km long ultra long seamless rail. Seamless rail to solve the thermal expansion and contraction by slot number is not enough, now solve the thermal expansion and contraction in two ways: one is the long rail itself under all temperature stress, will be locked in the long rail sleepers, which is due to temperature change and contraction, this method is suitable for throughout the year the temperature is almost the same as in the southern region, Chinese. In some temperature difference regions should take another approach, namely the long rail itself does not bear the temperature stress, and stress or regular bleeding stress to automatic bleeding, make the long rail with temperature rise and free shrinkage, at the time of laying also try to choose the best temperature of laying the rail expansion value in the minimum range, so that regardless of temperature rising or falling, the rail expansion always control in the smallest range.
In order to solve the problem of thermal expansion and contraction of rail fundamentally, the research group of seamless rail technology has studied and invented a new type of temperature force transfer structure - shear bonding structure. This structure uses solid solvent-free thermal curing adhesives will switch long core rail and wing rail, interval iron cemented into one, the shear strength of the adhesive, seamless line temperature force of an interval through switch to another normal transmission interval. Like Taiji, the force of heat and cold contraction will be transferred to the track next to it without accumulating on the seamless rail.
The seamless rail technology in China has been developed independently. The first step is to weld each 25 meter long rail in the welded rail mill into 250 meters long rails, and then use the long rail train to the construction site and weld them into 1 to 2 km long rails. After that, the long rail is connected with a section of a rail, and the rail is firmly buckled on the sleeper by a fastener.
