TBM operators completes India’s longest rail tunnel ahead of time
New Delhi, 07 Sep. 25 | By Jeevan Prakash Sharma (PTI)
India’s longest rail tunnel, stretching 14.57 km between Devprayag and Janasu in Uttarakhand, has seen the light of the day due to the perseverance of two tunnel boring machine operators who worked day and night to cut through treacherous mountain terrains and completed the project ahead of schedule.
The tunnel is part of the ambitious 125-km Rishikesh-Karnaprayag Rail Link Project, which the Railway Ministry has entrusted to Rail Vikas Nigam Limited to operationalise by December 2026
“It was a roller coaster ride in the real sense,” recalls Baljinder Singh, 44, a TBM operator employed with construction firm Larsen & Toubro (L&T), who has spent more than two decades navigating tunnels across mountainous terrain. Singh, along with 52-year-old colleague and veteran operator Ram Avtar Singh Rana, ran the TBM christened Shakti through solid rock, landslides, and debris to complete the task on April 16, 2025, twelve days ahead of schedule.
The challenges were formidable. A sudden landslide, three-and-a-half kilometres inside the mountain, blocked their path. “We normally operate the TBM at 50,000 to 60,000 kilo Newtons of force, but during that time, when it got stuck around 3.5 km inside due to a sudden landslide, I had to apply the machine’s full power, 1.3 lakh kilo Newtons, to clear the debris,” Singh said.
“The situation was so critical that it looked like the project might be shelved. It was our experience and patience, along with the technical and moral support of the whole team of over 200 experienced staff, that pulled us through,” he added.
For Rana, who cut his teeth in metro projects in Mumbai, the memory of those ten punishing days remains vivid. “It took nearly 10 days of non-stop struggle, working round-the-clock in 12-hour shifts to push the TBM through the muck. It was a huge relief and a joyous moment for the entire team when we finally cleared the blockage,” he said.
The operators emphasised that the machine could not be halted even for a moment. “We operated a German-made TBM named Shakti, running it non-stop in rotation, as stopping it for even a moment could have spelt disaster during that time,” Rana said.
The TBM itself was an engineering marvel: a 140-metre-long machine with a cutter head of 13.75 metres, equipped with 55 cutting discs. The civil crew followed its advance, grouting and stabilising freshly dug sections to reduce collapse risks.
Parallel to Singh and Rana’s achievement, Chandrabhan Bhagat and Sandeep Mishra were at work on a 13.09 km downline tunnel, separated by a 25-metre gap. On June29, 2025, that second tunnel also recorded a breakthrough. “After finishing the upline tunnel, all four of us focused on the downline, using the second German TBM named Shiv. Together, we set a new world record by advancing 790 metres in a single month (31 days),” Rana said.
According to L&T officials, the total tunnelling extends across 30 km, covering main tunnels, escape passages, cross-links, and niches. About 70 per cent of this was carried out by TBMs, with the rest relying on the drill-and-blast technique, known as the New Austrian Tunnelling Method.
Officials underlined the uniqueness of the operation. “That was the first time a TBM was used for a railway project in the Himalayan region. Such machines were previously used in the mountains only for hydroelectric tunnels,” an L&T engineer said.
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(Image Courtesy: Herrenknecht)
