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Happiness comes in many forms. For geologist Amit Rawat, elation is what he feels when he hears the sound of metal while he is test-drilling rocks. He looks out for something else, too: whitish boulders. These two are necessary for flawless tunnelling. Once he is assured of both — the sound and the colour — it is the time to pick explosives and trigger a blast to make tunnels.At Rojka Meo, a nondescript Haryana village on the Aravali hills, the rocks are of poor quality. But the engineers camping there since August 2019 to build a railway tunnel are confident that the geological challenges can be overcome.They have state-of-the art technology to mend the cracks and stitch the rocks. The 1-km-long tunnel, built as part of the western dedicated freight corridor (DFC) from Dadri in Uttar Pradesh to Mumbai, will need 350 blasts in total, each using 180-200 kg of explosives. 76363937For Rawat and his colleagues at the site, conquering the rock is easier than facing the challenges thrown by the novel coronavirus. As construction manager Sanjeev Kumar explains over the phone, the present situation has forced them to scale down the operation by 50%, as they need to adhere to social distancing norms. They are also facing frequent problems in the supply of materials, particularly explosives. “We wanted to see the big day — when both sides of the tunnel meet— in May, but because of Covid-19, daylighting will now happen only in August,” says Kumar, an employee of Larsen & Toubro, which is executing the project. This writer visited the tunnel in the second week of March and spoke to engineers over the phone later as well. 76363942This project in the Aravalis is one of the 200 railway tunnels that are at various stages of development in the country. These include 148 in the Northeast and 27 in Jammu and Kashmir. As the pandemic hit the nation, the geological hurdles seem minor for the Railways when compared with the Covid-19 troubles.The challenges include shortage of labour and disruption in the supply of materials, particularly sand in Jammu and Kashmir and explosives for the Aravali project. 76363947Also, for the resumption of work in each tunnel project, permissions need to be obtained from district magistrates. Work is further hampered by social distancing, which means bringing down the workforce by half; prohibition of 24×7 operations; and 14-day quarantine for migrant labourers returning from home. Meanwhile, procuring unskilled labourers from nearby villages is turning difficult as they are suspected and mocked at by people as potential carriers of virus.In J&K, where work has resumed in nine tunnels, including the 12.75-km-long tunnel in Ramban district that will soon be India’s longest, the procurement of sand is the key constraint, says an officer in the Rail Bhawan, on the condition of anonymity. At present, 11.2-km-long Pir Panjal, also in J&K, is India’s longest railway tunnel. Gotthard base tunnel in the Swiss Alps — measuring 57.1 km — is the world’s longest. 76363954With the pandemic delaying the proposed sand re-auctioning process in J&K, the Railways is negotiating with the local administration to find alternative ways, including taking over a mining site on a temporary lease, to tide over the crisis. Gammon Infrastructure Projects, Afcons Infrastructure and Hindustan Construction Company (HCC) are some of the private firms that are engaged in building the railway tunnels in the Rs 27,949 crore UdhampurSrinagar-Baramulla Rail Link (USBRL) project.It’s not an ordinary railway project. Out of a total route of 272 km in USBRL, 119 km are tunnels. At present, 11 tunnels in J&K are fully functional, with trains regularly passing through them. 76363958In addition, there are escape tunnels measuring 67 km — these are built parallel to the main tunnel for the purpose of emergency exit. Further, a provision for access roads to the tunnels for emergency exit and rescue services is added as an integral part of the project’s disaster management plan. Railways builds an escape tunnelwhenever the length of the main tunnel is three kilometres and above.“In the Kashmir project, we are passing through young fold mountains of the Himalayas. That itself is quite a challenge for building tunnels. We also face adverse climate with massive snowfall and landslides. Now, Covid-19 is a new challenge. Still, we have taken permission from district authorities and resumed work,” says Vijay Sharma, chief administrative officer of the USBRL project. 76363964He, however, refuses to comment on the possibility of shifting the 2022 deadline due to the pandemic.The question of extending deadlines is important as it bumps up cost. The more the delay, the greater will be the cost. Tunnel costs, in fact, vary depending on geology, location, specification and the size. A kilometre-long tunnel usually costs Rs 60-80 crore. But there are exceptions.The tunnel in the DFC corridor, for example, costs Rs 185 crore mainly due to its size and other features — like its diameter being double that of the tunnels in J&K. The escape tunnels, though, cost less — about Rs 25 crore per kilometre. 76363970While the USBRL project is a legacy of the UPA era — two legs involving 161 km out of 272 km were commissioned by July 2014 — railway projects in the Northeast got a boost during the NDA rule. If the average annual tunnel mining in the Northeast in 2009-14 was 6.3 km, it jumped to 12.6 km in 2014-19.Now 148 tunnels are being built in the region, and in terms of length, 87 km are completed. The 110 km Jiribam-Imphal line, executed at a cost of Rs 12,524 crore, has the highest number of tunnels in a Northeast project— 47.The Northeast has unique challenges: prolonged monsoon, prevalence of sandstones with high susceptibility to moisture, seismic vulnerability and occasional insurgency. An officer connected to the project says there is one more bottleneck now: barriers in inter-state movement. 76363978A senior railway officer tells ET Magazine that with the deployment of an advanced technology called the New Austrian Tunnelling Method a few years ago, India’s tunnelling activities have been fast-tracked both in J&K and the Northeast. “By 2022, our project in Kashmir and most parts in the Northeast will be completed,” he claims, adding that the line connecting Assam to Meghalaya (Tetelia to Byrnihat) is facing some land acquisition issues, and the first ever railway line in Sikkim — the 45 km Sivok-Rangpo line, being constructed at a cost of Rs 4,086 crore — is expected to be completed only by 2023. It will have 14 tunnels measuring 38.5 km.Tunnel mining could well be the mainstay of railway construction if the national transporter ventures into other geographies, including connectivity under the sea. In the design of Mumbai-Ahmedabad high-speed corridor, for example, there are eight tunnels, the highlight being the proposed 21-km-long undersea tunnel in the Thane creek, mainly to avoid a flamingo sanctuary and the nearby mangrove. 76363985The rest of the seven tunnels in the proposed flagship project are designed to pass through mountainous terrains in Palghar and Valsad districts of Maharashtra. Twenty more tunnels are being planned in the Bhanupali-Bilaspur-Beri line connecting Punjab with the hills of Himachal Pradesh.The chief of the DFC project, Anurag Sachan, anticipates delay in completing the tunnels he has been handling. “The beauty of tunnel construction is that we often encounter geological surprises, like a gush of water as we excavate. Covid-19 has also brought some surprises. The good news is that tunnelling has resumed though we anticipate a delay of six months or so in completing our tunnels,” he says.Sachan had earlier headed the USBRL project in Kashmir.In building tunnels, one works against nature. Only those who can control the rocks can win. “When perfect matching happens and we achieve daylight, we feel proud and happy. We have a good drink at every daylight,” says an engineer in the Kashmir project. The next cheers could take a while longer.

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