Kolkata East-West Metro: Work done, KMRC starts sealing 98-ft TBM shafts

Kolkata: KMRC has started sealing the last openings to the twin East-West Metro tunnels. The 98-feet deep shafts at the Esplanade metro station were built to launch the giant tunnel borers, Chundi and Urvi, in Jan-Feb 2019. A shaft is a vertical pathway that provides access to underground tunnels. Normally, metro shafts are closed months before the third rail (carrying electricity) is laid to prevent electrocution. Contractors ITD-ITD Cementation, which has built the last 2.6 km Esplanade-Sealdah leg of East-West Metro, took enormous risks to accommodate the drastic change in work sequence, allowing civil construction (tracks, pipelines, electric cabling, signalling work, etc) and train trials to proceed simultaneously and prevent further delay of the project.On Thursday, TOI sneaked a peek behind the cardboard partition that hides the 30m deep shafts from the East-West Metro's Esplanade station's functional area. The work will be over by July, said officials of KMRC, the implementing agency of East-West Metro, which is now veering toward its full 16.6 km run from Sector V to Howrah Maidan. The Esplanade-Sealdah section — the missing link between Sector V-Sealdah and Esplanade-Howrah Maidan — is finally ready for revenue operations.Ever since PM Modi inaugurated the 4.8km Esplanade-Howrah Maidan section (India's first under-river Metro), in March last year, the two shafts, one measuring 5.6mX4m to allow access to the west-bound or Howrah-bound tunnel, and another 3.1m-square opening for the eastbound or Sector V-bound tunnel, have been taking workers to the unfinished Esplanade-Sealdah section. The west-bound shaft was reduced from 10.5mX10.5m to its current size to make the subway linking East-West and North-South lines at Esplanade station more spacious.The shaft closure involves construction of four slabs to cover each of the twin tunnels. The east-bound shaft has two are hatch covers (steel structures through which tunnels can be accessed during emergencies) and two concrete covers. The west-bound shaft will have one hatch cover and three concrete slab covers.