MAHARASHTRA, INDIA (Metro Rail News): Maha Metro has completed flash butt welding (FBW) for the track being laid on Reach II (Sitabuldi to Automotive Square) and Reach IV (Sitabuldi to Prajapati Nagar). The organization mostly did FBW as these welds are stronger than other ones.
Rails used in Nagpur Metro Rail Project (NMRP) are generally of length 18 meters and 25 meters. The individual rails are welded together to form long-welded panels of various lengths according to the alignment of the track.
Rail welding is generally done by two methods:
Flash butt welding (FBW): These welds have 95% strength of their parent rails as the metallurgy of rail is not changed during this process. This process is adopted for making long weld rail (LWR) panels before casting track plinths.
Aluminium thermit welding (ATW): The process involves pouring molten iron metal between two rail panels, where a gap of 25 millimeters is left. The metal acts as the glue between parent rails. This process is generally adopted to convert long weld rail (LWR) panels into continuous weld rail (CWR) panels after track laying work is finished. These welds have 45% strength of parent rails as external material is poured between rails.
In Nagpur Metro, 18 meter and 25-meter rails have been welded to form an LWR panel of an average length of 350 meters. The longest rail panel made at NMRP is of length 600 meters with twenty-four 25 meter long rails.
In Reach II and IV, a total of 3,064 flash butt welds has been done to complete 100% rail panels in the month of October. The use of ATW is only 10% of FBW in Nagpur Metro. This has been done so that the track has maximum strength.