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.