Fourteen portal beams spanning the Delhi-Mumbai Rajdhani railway line at Vadodara in Gujarat have been installed, marking a construction advance for the Mumbai-Ahmedabad high-speed rail corridor. Elevated-track construction for what would be the country's first bullet train line advanced with the completion of this phase of work.
Forty-metre composite girders are set to be lifted into place as crews push the elevated viaduct forward, following the completion of the portal beams. Within Vadodara, the rail corridor designated for the Mumbai-Ahmedabad High-Speed Rail project covers a distance of around 8.3 kilometres.
Five railway corridors managed by Indian Railways — among them two trunk routes and the heavily trafficked Delhi-Mumbai Rajdhani line, which the alignment crosses at an angle — fall within the span of this section. The National High Speed Rail Corporation Limited (NHSRCL) noted in its release that building above a functioning rail corridor brings a distinct set of engineering and operational demands, and that the newly completed spans satisfy a structural prerequisite for deploying 40-metre composite girders across the Rajdhani main line, thereby allowing the elevated corridor to advance through that stretch.
Hefty horizontal beams known as portal frames sit beneath the elevated viaduct, bearing the load of the trackway on which the bullet train travels. Where high-speed rail routes cross over existing lines, these junctions carry a heightened level of operational importance.
Portal beams at the Vadodara stretch were cast in place rather than prefabricated off-site, with NHSRCL noting that active railway operations running through the area, combined with limited working space, left on-site casting as the only viable construction approach. Spanning 37 metres in length, standing 4 metres tall, and 4 metres across, each of the beams carries a weight of roughly 1,500 tonnes.
Each beam drew on roughly 590 cubic metres of poured concrete, along with a steel reinforcement cage weighing around 55 tonnes. With all 14 portal beams set in place, installation of the 40-metre composite girders — the phase that follows portal beam assembly — can now get under way.
Advancing the steel beams along the bullet train corridor positions the elevated viaduct further ahead along the route. Building out the corridor linking Mumbai and Ahmedabad with high-speed rail capacity depends on this phase of work, a spokesperson noted, adding that erecting these structures draws on a fleet of high-capacity cranes, hydraulic jacking systems, extended-boom concrete pumps, and precision surveying tools.
Building several structures directly over live railway lines requires the work to be staged in a precise sequence, with ongoing monitoring, close coordination with Indian Railways, and controlled track-access windows put in place as needed, NHSRCL noted.
