Indian Railways has achieved another engineering feat. The engineers of Indian Railways has added another feather in its cap by commissioning the longest electrified tunnel in India.

The total length of the tunnel is 6.6 kms and is situated between Cherlopalli and Rapuru stations which fall under the South Central Railways zone of Indian Railways. The newly constructed tunnel will help in providing viable rail connectivity between Krishnapatnam Port and its hinterland for goods train services.

The newly constructed tunnel will help in reducing the travel time by 5 hours. At present, the average travel time taken by goods train from Krishnapatnam Port to Obulavaripalli is 10 hrs.

The construction of this tunnel paved the way to operate freight trains in Obulavaripalli - Venkatachalam - Krishnapatnam Port new railway line for a distance of 113 Kms. The section is now notified for commercial freight operations as well. This new line facilitates direct & viable connectivity between South Coast and West Coast.


Salient Features of 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.

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