On Monday, Chennai Metro Rail Limited (CMRL) marked a new milestone with the installation of the country’s longest precast U-girder — a 33.33m span — at Ramapuram, as part of Phase 2 Corridor 5 (Madhavaram-Sholinganallur). This surpasses the previous national record of 31m held by Bengaluru Metro.While most girders in Chennai measure about 25m, with 30m spans seen along OMR, this achievement was realised in collaboration with general consultant AEON and contractor L&T. U-girders are large, concrete beams positioned between two pillars to support metro tracks and enable faster construction, improved load handling, and quieter train operations, especially beneficial in dense urban stretches such as Ramapuram.Typically, longer spans at traffic junctions and U-turns are built using steel girders to accommodate future road widening. However, CMRL opted for a longer U-girder outside the L&T headquarters, combining structural efficiency with aesthetic design. “This will also help us cut costs to nearly half of what a steel girder would require,” says CMRL Director (Projects) T Archunan.Casting the 225-tonne girder required specially fabricated moulds and complex pre-tensioning processes to ensure quality. Six such girders were launched over three spans, with two girders per span. To transport each girder from the Kolapancheri casting yard 18km away, L&T deployed multi-axle trailers and secured police permission to divert traffic and clear hindrances en route.Once onsite, the installation process was completed within five days. CMRL officials confirmed that similar long-span U-girders would be considered in future alignments to optimise cost and execution timelines.In a related development, the Tamil Nadu govt granted in-principle approval to extend Chennai Metro Phase-II Corridor 4 (Light House-Poonamalle) to Parandur in two stages, aimed at connecting the upcoming greenfield airport and the intercity bus terminal at Kuthambakkam. According to a govt order dated May 30, the project will span 52.94 km and be executed in two phases: Phase-I (Poonamallee–Sunguvarchatram, 27.9 km) was cleared for implementation at an estimated ₹8,779 crore. The detailed project report, prepared by Aarvee Associates and submitted by CMRL, was approved by the state and recommended to the Centre for funding on an equity-sharing basis and through external loan assistance.