What are the usual neutral temperatures for continuously welded rail? What equipment does IR use for track destressing?
IR divides the country into five zones based on the normal temperature variation expected in each region. The maximum rail temperature difference is about 70C (ranging from a minimum of -5C to a maximum of 60C or so — the rail temperature can be several degrees higher than the ambient temperature. The neutral temperature or stress-free temperature for CWR is usually fairly high, 40C or even higher in some locations depending on expected summer temperatures — it is usually 5 to 10C higher than the expected mean temperature for the zone’s range. Track destressing is carried out when the ambient temperature is high, not much below the maximum that is normally attained in the area. Switch expansion joints (SEJ) are provided at the ends of long welded rails to allow for the cumulative thermal expansion movements of the ends of the rails. Most SEJs allow for a movement of the ends of the rails of about 120mm, but there are some SEJs with a maximum gap of about 190mm. Because of the high ne
