Kolkata: The Metro Railway will undertake thorough rail renewal on the 25.33-km stretch of the North–South corridor (Blue Line) between Noapara and Kavi Subhash, covering both up and down lines, to address ageing track infrastructure.
The authorities have already floated a tender for the work, with the project estimated at Rs 4.20 crore.
The project involves the replacement of existing rails with 60 kg rails on ballastless track across underground, surface and elevated sections. The work is to be completed within 12 months. The scope includes removal and insertion of rails and fittings, drilling and cutting of rails, epoxy grouting of inserts, and refixing of components after lubrication. It also covers handling, lifting and transportation of rails, sleepers and track fittings.
Engineering works will involve repair of track beds, including cleaning of concrete surfaces, removal of damaged material and relaying using cement mortar and polymer-based compounds. Replacement and adjustment of pads, bearing plates and fastenings, as well as alignment corrections, are part of the contract.
The tender also includes rail surface treatment with anti-corrosive coatings and repairs to central and side drains to improve drainage and track stability.
The renewal comes against the backdrop of structural concerns on the 41-year-old corridor, with officials citing subsidence of tracks in certain stretches, water seepage through tunnel walls and damage to platforms. “Wear and tear has accumulated over the years despite routine maintenance,” a Metro official said.
The North–South corridor began operations between Esplanade and Bhowanipore (now Netaji Bhavan) on October 24, 1984, and became fully operational between Tollygunge (now Mahanayak Uttam Kumar) and Dum Dum on September 27, 1995.