Ahmedabad: In a one-of-its-kind operation, one of the heaviest precast prestressed portal beams (girders), weighing approximately 1,360 metric tonnes, has been launched over the Ahmedabad–Vadodara railway line in Maninagar for the Mumbai–Ahmedabad Bullet Train project, the National High Speed Rail Corporation Limited (NHSRCL) said on Wednesday.

The portal beam is a precast concrete structure measuring 34 metres in length, with a cross-section of 5.5 metres by 4.5 metres. A total of five such beams are planned for installation near Maninagar railway station. These beams are being precast on-site and erected as heavy integrated units.

The entire launching activity was executed under strict safety protocols within a remarkably short duration of around 3.5 hours. This was achieved during a full traffic and power block coordinated with Indian Railways. Earlier, the same operation was planned with long-duration caution orders extending up to six months and requiring blocks of nearly nine hours. Through meticulous planning and optimisation, the execution time was significantly reduced to just 3.5 hours for both lines of the Ahmedabad–Vadodara section.

The lifting operation was carried out using a 2,200 MT crawler crane as the primary equipment, supported by auxiliary machinery including a 260-tonne standby crane, an 80-tonne crane, man lifters, and a lifter beam system with anchoring frames. The lifting arrangement utilised prestressed Macalloy bars of 75 mm diameter, along with lifting beams and heavy-duty slings to safely handle the massive load.

The operation presented several engineering challenges, including handling an ultra-heavy lift of around 1,360 MT, one of the heaviest lifts executed over Indian Railways infrastructure, while completing the entire erection within a limited time window.

Additional complexities included restricted working space, the presence of overhead equipment (OHE), and multiple active railway lines. These factors required high precision during placement at an approximate pier height of 15 metres, real-time coordination with railway authorities, deployment of redundant lifting systems, rigorous rigging checks, continuous wind speed monitoring due to the large exposed surface area of the beam, and precise survey and alignment control to ensure safe and accurate installation. DeshGujarat