Andhra Pradesh gets India's longest electrified rail tunnel. Key features

Vice President M. Venkaiah Naidu on Sunday inaugurated India's longest electrified rail tunnel. Situated between Cherlopalli and Rapuru stations of Andhra Pradesh, the 6.6-km long tunnel is a part of the Obulavaripalli-Venkatachalam railway line.

The newly constructed tunnel will provide seamless rail connectivity between Krishnapatnam Port and the hinterland areas for freight movement.

The 112-km long electrified railway line between Venkatachalam and Obulavaripalli will reduce the the travel time by 5 hours. Currently, the freight train takes 10 hours to travel from Krishnapatnam Port to Obulavaripali. Venkaiah Naidu termed the tunnel an "engineering marvel."

“I am overwhelmed with emotion as my long-cherished childhood dream has now come true,” the Vice President said about his trip on the newly-commissioned Obulavaripalli-Krishnapatnam line.

Some of the salient features:

— The country's first electrified tunnel is built in the shape of a 'horse shoe' using the New Austrian Tunneling Method (NATM).

— Construction of the tunnel was a major challenge as the tunnel area was full of quartzite and phyllite rocks. The tunnel construction was completed in a record time of 43 months.

— Built at a cost of ₹437 crore, Vice President M. Venkaiah Naidu termed the tunnel "an engineering marvel."

— The height of tunnel (rail level to roof) is 6.5 meters and the minimum height of contact wire is maintained at 5.2 meters.

— The track is constructed without using Ballast by providing Bi-block sleepers and Vaslo fittings.

— Two sub-stations for supply of electric traction power are provided near Cherlopalli and Adurupalli with necessary switching stations in between.

— Over Head Equipment (OHE) maintanance depot is provided at Rapuru along with tower-car shed.

— There are LED lights at an interval of every 10 metres inside the travel.