Kolkata: Kolkata Metro will revamp the four-decade-old AC and ventilation system between Rabindra Sarobar and Belgachhia stations in the North-South or Blue Line.
There are 15 underground stations in this 16.9 km Blue Line section. Each of these 15 stations has centralised AC systems that include water-cooled chillers, towers, coils and ducts through which cool air is released into the platform, concourse and mezzanine levels.
However, these were built when India’s first underground metro was launched on 24 October 1984 and are now considered primitive. Kolkata Metro will spend Rs 500 crore for replacing them with modern HVAC systems.
The tender has been floated for overhauling the environmental control system (ECS) and replacing the AC and ventilation of the twin tunnels.
The tender process is likely to end this month. The work will take four to five years, as unlike greenfield Metro projects, the commercial operations will continue uninterrupted.
The basic design of the North-South Metro was done by IIT Kharagpur in 1984, but the equipment now needs upgradation and replacement due to the passage of time. Therefore, RITES was engaged to conduct a health study.
The work is mainly aimed at ensuring cooler stations and tunnels. It will also improve the fire safety system, making sure there is proper ventilation inside the tunnels when a fire breaks out and passengers need to be evacuated.
Both the AC and ventilation systems will be upgraded due to the current ambient temperature, which has risen considerably since 1984.
Surface stations like Dum Dum, Noapara and those between Mahanayak Uttam Kumar (Tollygunge), Shaheed Khudiram and Kavi Subhash (New Garia) do not have cooling units.
