Indian Railways have added another record to its kitty as the South Central Railway Zone successfully commissioned the longest electrified tunnel in India, that too, in a record time. The 6.6 km tunnel was built between Cherlopalli and Rapuru stations at a total cost of ₹460 crore.
On June 25, two freight trains successfully ran on this line, marking the full-scale operation of the tunnel, the construction of which was completed in record 43 months.
The tunnel will enable the Railways to start freight operations on this important railway line, which has reduced the distance between Krishnapatnam Port and hinterland areas by 60 km. At present, the average travel time taken by goods train from Krishnapatnam Port to Obulavaripalli is 10 hours. On the newly commissioned line, the travel time gets reduced to about 5 hours.
The tunnel also paves way for operating freight trains in Obulavaripalli - Venkatachalam - Krishnapatnam Port new railway line for a distance of 113 km, the South Central Railway said in a release.
Key facts about the tunnel
Located between Cherlopalli to Rapuru stations and constructed in shape of ‘Horse Shoe’.
New Australian Tunneling Method(NATM) is used and the cost incurred is Rs.460 crores
Length of the tunnel is 6, 660 mts and is in straight alignment.
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.
Ballast less Track is constructed with Bi-block sleepers and Vaslo fittings
Full length lining is provided with 300 mm thickness
Two nos. of traction power supply substations are provided near Cherlopalli and near Adurupalli with necessary switching stations in between.
OHE maintenance depot is provided at Rapuru along with tower-car shed.
LED lighting provided at 10 m intervals inside the tunnel
Conventional OHE has been provided with a maximum span of 36 m and maximum tension length of 1206 m. Brackets for supporting OHE have been fixed on wall mounted type plate fittings, which are fixed to the tunnel lining concrete.
Spring type Auto Tensioning Device (ATD) of South Korean make is adopted in place of conventional type ATD for maintaining necessary tension in OHE wires, for the first time in SCR.
Fail safe earthing arrangements are provided for safety of personnel working in tunnel.