Indian Railways commissions longest electrified tunnel between Cherlopalli-Rapuru Station

New Delhi: South Central Railway has commissioned the longest electrified tunnel, measuring 6.6 Kms between Cherlopalli and Rapuru stations and is part of the recently completed Obulavaripalli – Venkatachalam new railway line.

The tunnel has been completed in a record time of 43 months.

Two freight trains have successfully run on 25th June, 2019 marking the full-scale Operation of the newly built electrified railway line between the two stations, thereby opening up viable rail connectivity between Krishnapatnam Port and its hinterland for Goods train services, South Central Railway (SCR) said in a statement.

Completion of this tunnel has enabled Railways to start freight operations on this important railway line, which has reduced the distance between Krishnapatnam Port and hinterland areas by 60 kms. At present, the average travel time taken by goods train from Krishnapatnam Port to Obulavaripalli is 10 hrs. On the newly commissioned line, the travel time gets reduced to about 5 hours, which will result in a saving of travel time by 5 hours, it added.

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.

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.
• This longest electrified tunnel is pivotal in the new railway line between Venkatachalam and Obulavaripalli and is a game changer in the freight operations of the zone.
• This new line facilitates direct & viable connectivity between South Coast and West Coast and enhances the freight basket of South Central Railway.

Gajanan Mallya, General Manager, SCR said that it is a matter of pride for the zone to have such remarkable structure. The newly constructed railway line is also helpful for decongestion of traffic on Vijayawada - Gudur Main line.