Valsad: The work for constructing a mountain tunnel under C4 package (Design and Construction of 237 km length of viaduct between Vapi and Vadodara in the state of Gujarat including four stations namely Vapi, Bilimora, Surat, Bharuch and Surat Depot) is progressing well. This is the only tunnel in Mumbai-Ahmedabad High Speed Rail Corridor (MAHSR) C-4 package.

The under construction mountain tunnel is located at around 1Km away from Zaroli Village of Umbergaon Taluka in Valsad district of Gujarat. The tunnel structure comprises of tunnel, tunnel portal and other connecting structures like tunnel entrance hood.

The tunnel is being constructed by New Austrian Tunnelling Method (NATM) which includes the following procedure:

1. 1. Marking of drill holes on the tunnel face
2. 2. Drilling of holes
3. 3. Charging of explosives
4. 4. Controlled Blasting
5. 5. Removal of muck (blasted rock pieces)
6. 6. Installation of primary support which includes steel ribs, lattice girder, shotcrete, rock bolts based on the type of rocks as assessed by geologist after each blast

The Mumbai-Ahmedabad rail corridor is being constructed for the operation of bullet train between Mumbai and Ahmedabad. The mountain tunnel in Umargam will be 350 metres long with a diameter of 12.6 meters. The tunnel’s height is 10.25 metres, in the shape of a single-tube horseshoe. Two tracks will pass through the tunnel.

MAHSR corridor will have seven mountain tunnels, which will be constructed using the NATM Method. DeshGujarat