On Friday, Prime Minister Narendra Modi is likely to flag off two specially designed Vande Bharat trains between Srinagar and Katra, marking the completion of a 42-year-old project to link Kashmir with the rest of the country via trains.Of the last stretch of the 272-km Udhampur-Srinagar-Baramulla Rail Line (USBRL), the 118-km Qazigund-Baramulla section was commissioned in October 2009, followed by an 18-km stretch between Qazigund and Banihal in June 2013, Udhampur-Katra (25 kms) in July 2014 and Banihal-Sangaldan (48.1 km) stretch in February 2024.The remaining 63-km Katra-Sangaldan section is to be commissioned on June 6, and it is this section where the Prime Minister will also be inaugurating the world’s highest railway bridge over Chenab.Built at a cost of around Rs 14,000 crore, the Chenab bridge is the highest rail and arch bridge in the world with a dock height of 359 meters from the river bed, 35 meters taller than Paris’s iconic Eiffel Tower.A 1,315-meter steel arch and concrete structure, consisting of a 530-meter approach bridge and a 785-meter deck arch bridge (the part of the bridge on which vehicles run), it is considered India’s most recent marvel in civil engineering.What were the challenges involved in its construction?Built between Bakkal and Kauri in Reasi district, the bridge falls in zone-V, a major seismic zone with a fractured geology. One of the biggest challenges was to build the bridge without obstructing the flow of the Chenab river.In the absence of any road link, carrying heavy machinery and material to the site was another big challenge.Who did what?Story continues below this adOverseen by the Konkan Railway Corporation, the bridge’s design and construction was awarded to a joint venture consisting of Afcons Infrastructure, South Korea-based Ultra Construction & Engineering Company, and VSL India. While the Finland-based WSP Group and Germany-based Leonhardt Andra and Partners designed its viaduct and foundations, and arch, respectively, the Indian Institute of Science, Banglore, prepared a design for its foundation protection. The Indian Institute of Technology, Delhi, analysed the slope stability. IITs Delhi and Roorkee did seismic analysis, while the Defence Research and Development Organisation (DRDO) helped in making the bridge blast-proof.How was its construction completed?The Chenab bridge was proposed in one of the most complicated and isolated terrains in India. Its deck is located on a transition curve (the part between straight and circular sections of roads) with changing radius. The bridge’s construction, thus, was carried out in stages.The Steel Authority of India provided steel and a Swiss company, Mageba, supplied spherical stopper bearings for the bridge, which involved fabrication of 28,660 MT of steel for 26 km of motorable roads.The sophisticated Tekla software, which builds 3D models of buildings or infrastructure projects, was used for the bridge.Story continues below this adWhat is the life of the bridge and how safe is it?It is designed to have a lifespan of 120 years and handle train speeds upto 100 km per hour. It can withstand earthquakes up to a magnitude of 8 on the Richter Scale, besides high-intensity explosions equivalent to 40 tonnes of TNT.Its steel structure can withstand temperatures up to -20 degree C and wind speeds up to 266 km per hour. Even after the removal of one pier, it will remain in operation at a restricted speed of 30 km per hour.