Explained: Why the bridge Modi inaugurated makes India proud

Asia’s first vertical-lift sea bridge, which will pave the way for resumption of train services up to Tamil Nadu’s Rameswaram island after two years, has been inaugurated. Rameswaram, situated some 500 km from Chennai, is one of India’s Char Dham pilgrimage destinations.The bridge connects the island with Mandapam on the mainland (Ramanathapuram district). It will reduce the train travel time between these two towns to five minutes from the earlier 25-30 minutes. medium nocaption118378011The new structure, which runs parallel to the century-old railway bridge, could eventually replace the latter. The British-era bridge featured a manually operated horizontal opening mechanism to facilitate ships’ movement below.Situated in the Gulf of Mannar, the 2.1-km long new bridge has been built at a cost of Rs 535 crore. Railway minister Ashwini Vaishnaw has hailed it as “a symbol of progress, connecting people and places with modern engineering”.The work on the bridge commenced in 2019 after the foundation stone was laid by Prime Minister Narendra Modi. 118383370A modern marvel It is a movable bridge, in which the central span (the horizontal structure between both supports) rises vertically while remaining parallel with the deck. This allows seamless movement of maritime traffic.“The lifting of the old bridge is done manually whereas the new bridge will be operated by an electro-mechanical system, which will be interlocked with train control systems for operation of the navigational spans,” explains R Srinivasan, senior deputy general manager of Rail Vikas Nigam Limited (RVNL), the construction arm of the Indian Railways. “It is unique because it is the first vertical lift bridge in India. It is the first of its kind in Asia as well,” he told The Indian Express earlier. medium nocaption118384229The bridge is supported by 336 piles made of stainless steel. Stainless steel reinforcement was used throughout the bridge, as per the guidelines of the Railway Design and Standards Organisation (RDSO) that mandates that any bridge constructed within 30 km of the sea must use stainless steel reinforcement instead of ordinary steel, to combat corrosion. The substructure of the bridge has been built in such a way that it will pave the way for double lines in future. The new bridge will allow trains to run on electrical traction while the old bridge was meant for diesel locomotives.Watch how the new bridge operates: medium nocaptionhttp://www.youtube.com/watch?v=HA35TY2FPEUWhy another bridge?The necessity for a lift bridge emerged from several constraints. A road bridge already spans the existing rail bridge, making the construction of a new bridge at a higher elevation impractical without disrupting the existing structure.Moreover, the area's coastal winds, which average around 40 kmph daily, posed another challenge. Building a sea bridge at a higher elevation could potentially create safety risks, as the strong winds might destabilise train coaches. medium118383543The new bridge has been modelled on similar moving rail bridges in Germany and Spain. RVNL experts had visited Spain’s Valencia and Barcelona and Germany’s Hamburg port to study similar structures. Valencia’s rail bridge swings horizontally for ferry movement. Barcelona’s double bascule bridge opens vertically and Hamburg port features a vertical lift bridge similar to the new structure at Pamban. “However, it [the Pamban Bridge] is not a mere replica of the Hamburg bridge,” says RVNL chief project manager TK Padmanabhan. The bridge was designed by Spanish firms, which had to consider the difficult marine conditions of Pamban, as well as its position in a region prone to cyclones and high winds. medium nocaption118384181Ensuring faster train travelThe Indian Railways will decide whether to dismantle the iconic 111-year-old Pamban Bridge, a double-bascule movable structure, after the new one is opened for traffic, according to officials. The old railway bridge, that was commissioned on February 24, 1914, showcased one of the most advanced technologies of that that. It served as the only link between the mainland and Rameswaram, home to the famous Ramanathaswamy Temple, and the popular tourist spot of Dhanushkodi until the construction of a road bridge parallel to it in 1988. medium nocaption118381848Besides being India's first sea bridge, it was also the longest in the country until the opening of Mumbai's Bandra–Worli Sea Link in 2010The old bridge was shut for train traffic in December 2022, after the sensors fixed to monitor its health had detected certain glitches. The old bridge had a speed limit of 10 kmph on the lift span but the new structure will allow a maximum speed of 50 kmph on the central span and 75 kmph on the rest of the bridge.This will allow trains to cross the sea in less than 5 minutes, significantly reducing the earlier 30-minute travel time, railway officials claim. Seventeen mail/express trains can use this bridge in a day.After the closure of the old rail bridge, maritime traffic between the Bay of Bengal and the Arabian Sea was diverted via Sri Lanka’s boundary in the Indian Ocean. The opening of the new navigational channel will help save time and money for shipping vessels, and connect Rameswaram with mainland India via rail again.