Thiruvananthapuram: Southern Railway has given its approval to the detailed design of a new tunnel to be built at Balaramapuram as part of the much-anticipated doubling of Thiruvananthapuram–Kanyakumari railway line, railway sources confirmed to TOI. The endorsement came after design scrutiny by experts from IIT Madras. This has cleared a major technical hurdle in the ongoing expansion work.The proposed new tunnel, to be constructed next to the existing single-track tunnel, will be about 200m long and 16m wide. Because the soil in the area is prone to instability and landslides, engineers will use the pile and wall method, a technique that creates reinforced vertical support before excavation. Once built, the tunnel will support the double-line railway section, enabling more frequent and faster train movements between the state capital and the southern tip. Current traffic through the old tunnel is restricted by speed limits and operational constraints, officials said. Construction is estimated to cost around Rs 30 crore, with a project timeline of eight to 12 months. The existing tunnel is expected to be decommissioned once the new structure is operational. “This approval marks a significant step forward in addressing the longstanding bottlenecks on Southern Railway’s Thiruvananthapuram–Kanyakumari corridor,” said a railway source, explaining that the new tunnel would not only facilitate the doubling of tracks but would also improve safety by mitigating landslide risks during monsoon. “We anticipate smoother services and reduced delays once this work is completed,” the spokesperson added. The construction contract was awarded to a Kochi-based company, and preparatory clearing of soil and debris on the site has already been initiated. Subsequent heavy machinery and equipment are expected to arrive on site shortly. The doubling project also includes ongoing earth-strengthening works along landslide-prone sections of the route, which railway engineers believe would enhance the overall resilience of the line.
