The Indian Railways has created another milestone successfully. The South Central Railway zone has commissioned the longest electrified tunnel. The 6.6 Km long tunnel is situated between Cherlopalli and Rapuru railway stations. For the first time, advanced technologies have been brought in by South Central Railway, instead of conventional type Auto-Tensioning Device(ATD), Spring type ATD of South Korea for maintaining necessary tension of OHE wires. New Australian Tunneling Method (NATM) has been used with an estimated cost of 460 crores. The height of the tunnel is 6.5 meters whereas the minimum height of the contact wire is maintained at 5.2 meters, the ballast-less track has been constructed. Two traction power supply substations have been provided near Cherlopalli near Adurupalli with necessary switching railway stations in between. The tunnel has been completed in record 43 months, enabling Indian Railways to start freight operations on this crucial line, which has reduced the distance between Krishnapatnam Port and its hinterland areas by 60 km. Inside the tunnel, LED lighting has been provided at 10 meters intervals. Till now a goods train took an average 10 hours to travel from Krsihnapatnam Port to Obulavaripalli. After the newly electrified line, the travel time gets reduced to about 5 hours. The tunnel has opened the way to operate freight trains in Obulavaripalli-Venkatachalam-Krsihnapatnam Port line for a distance of 113 Km. The tunnel will act as a game changer in the freight operations of the zone.