Seamless Rail And Long Rail
Continuous Welded Rail (CWR), also known as seamless rail or long rail, is a rail connection method where steel rails of several thousand meters in length are welded together without any joints. This technique offers several advantages, including increased rail strength, reduced maintenance requirements, and smoother train operation.
One of the primary challenges associated with CWR is managing the effects of temperature variations, including cold shrinkage and thermal expansion, which can cause stress and deformation in the rails. To address this issue, several methods are employed:
Pre-stressing: Rails are stretched before installation to simulate thermal expansion. This pre-stressing helps to counteract the effects of cold shrinkage and ensures that the rails remain within acceptable tolerances during temperature fluctuations.
Temperature Locking: The temperature of the railway track is calculated based on local maximum and minimum temperatures. By locking the temperature of the track within a specified range, the expansion pressure of the rails due to temperature changes can be minimized.
Fixed Installation: Rails are securely fixed to reinforced concrete sleepers, which limits their freedom to expand and contract. This fixed installation method helps to maintain track stability and reduce the risk of rail buckling or warping due to temperature variations.
