Sunday Drive by Hormazd Sorabjee: Exploring the Atal Tunnel

What’s so special?

First, it’s a massive feat of engineering and this 9.02 km tunnel is the longest in the world above an altitude of 10,000 feet and its staggering to know that there’s still about 2 km of mountain above the tunnel roof. Just imagine how hard it must have been to blast a hole through a gigantic mountain of rock, in sub-zero temperatures in winter.

Built by the Border Roads Organisation (BRO), the Indian military’s civil engineering and road building arm, the Atal tunnel was possibly its most challenging project. “The fact that the tunnel has almost 2 km of mountain above it meant that complex support systems had to be designed to counteract the stresses on the tunnel boundary,” says Colonel Parikshit Mehra, the BRO’s project director for the Atal tunnel. However, what the BRO hadn’t bargained of is the Seri Nala Fault, the longest shear or fault zone encountered by any highway tunnel in the world. “The 600-metre excavation across the Seri Nala fault took four years to cross while the rest of the 9.02 km tunnel was also excavated in the same time,” says Colonel Parikshit. Building such a complex and long tunnel against huge odds was baptism by fire for the BRO and with the accomplishment of the Atal tunnel, Parikshit says, “India has arrived in the world of tunneling.”

Making a difference

But it’s how the Atal Tunnel has changed the lives of the people in the region, which is of greater significance. For one, bypassing Rohtang cuts the distance by 46 km. That may not seem like a lot but it’s a treacherous 46 km on rough, narrow roads that adds a couple of hours to the journey. The biggest impact the tunnel has is on the lives of the people in Lahaul and Spiti and beyond. Cut off every year for six months over winter because of heavy snowfall that blocks Rohtang, the tunnel now gives all year access to Manali and is a lifeline to the rest of the world.

To appreciate this marvel of engineering, I’ve brought along a marvel of automotive engineering, the mountain-stirring 600hp Audi RSQ8.

It’s an expectedly scenic drive up from Manali with fir trees lining the entire route. The roads are smooth and well-marked and at the South Portal of the tunnel, there’s a massive ceremonial gate to welcome you.

The entry of the tunnel is lit up like a stadium and a pleasant surprise from the dingy mountain tunnels we are accustomed to. After 200 metres, the lighting isn’t as bright, so the RSQ8’s brilliant LED headlamps come in handy. Cruising through the tunnel, I feel I could be anywhere in Europe. All the signage, like the speed limits, exits and emergency phone locations, are clearly marked. And there’s an escape tunnel built-in too, for emergencies. Also, should the air quality inside the tunnel deteriorate, fresh air can be pumped in from either end.

Except at the beginning and end, the tunnel is arrow straight throughout, and it’s a place where I can theoretically test the RSQ8’s top speed of 305kph. But there are strict speed limits of 40kph and 60kph in the tunnel. Also, there’s no overtaking in the Atal Tunnel and you drive in a single file. It still beats the narrow roads and stomach churning climb up the Rohtang Pass, though.

The 10 minutes it takes to cover the Atal Tunnel feels like time travel and it’s when you emerge on the other side and look up at the mighty mountains, which until now were a natural barrier in the winter months, the enormity of what the tunnel has achieved sinks. The late Atal Bihari Vajpayee must be smiling from up above.

The views expressed by the columnist are personal

From HT Brunch, February 7, 2021

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