Metro eyes 3-minute gap by 2030, 90-second headway later with massive Blue Line revamp
Telegraph | 28 November 2025
Calcutta: Metro Railway has lined up a series of infrastructure upgrades to improve the frequency of trains on the Blue Line, the oldest Metro link now plagued by snags and delays.
Now, the Blue Line has a peak-hour frequency of five minutes. “We aim to bring it down to three minutes first and eventually attain a headway of 90 seconds,” said a senior official. The three-minute gap is expected to be achieved by 2030, he said.
Metro had reported that the carrier had engaged consulting agency Rites to conduct a study on how to overhaul Metro tunnels between Tollygunge and Dum Dum, which are over 40 years old. This includes rebuilding the civil structures, tracks, and the electrical and signalling system. It could take four to five years.
“Improving the service frequency would also require upgrading of infrastructure,” said Subhransu Sekhar Mishra, the general manager of Metro Railway.
“We are trying to find a solution that will allow us to continue services while carrying out this upgrade work, so that the commuters are not inconvenienced. We are looking for references in old Metros like London and Moscow,” said Mishra.
Substations
Metro engineers said running trains at shorter intervals has some prerequisites. Each station should have a traction substation; the steel third rail should be replaced with aluminium; the signalling system should be upgraded to the communication-based train control system (CBTC), and the maximum speed of trains should be increased.
Seven additional traction substations will come up along the Blue Line network, a spokesperson for the carrier said. A substation receives power from the CESC and feeds it to the third rail at stations. The third rail provides power to the trains. The new ones will be built at Kalighat, Netaji Bhawan, Maidan, Esplanade, M.G. Road, Sovabazar and between Belgachhia and Shyambazar.
The Blue Line now has 19 substations. Nine more would mean a substation for every station.
“Of the nine additional substations, we have already placed orders for two — at Chandni Chowk and Gitanjali (Naktala). The equipment for these two substations has already arrived. These two substations are expected to be ready by April next year. For the remaining seven, a detailed estimate will be sent to the Railway Board for the final sanction of funds,” said the Metro official.
Third rail
The existing third rail, made of steel, is being replaced with one made of aluminium, in phases. Aluminium is a much better conductor of electricity than steel. Aluminium third rail will reduce the system voltage drops and subsequent energy losses. Fewer voltage drops will help achieve faster train acceleration.
The second phase is nearing completion. It will cover most of the underground section. In the third phase, the elevated section between Tollygunge and Kavi Subhas (New Garia) will be covered.
Aluminium third rail and traction substations are capable of reducing the gap between two trains to three minutes. Additionally, there have to be two ventilation zones between two adjacent underground stations, as prescribed by railway norms. “The orders for equipment have already been placed to improve the ventilation system. The new system should be ready by 2028,” said the official.
Signalling
For a 90-second headway, the carrier needs the CBTC system and increased maximum speed.
The Blue Line is now operated through the train protection and warning system (TPWS). It will be augmented to the more advanced CBTC system, in which a train picks up signals from the tracks and turns into a moving block.
The Railway Board has already sanctioned the money for the CBTC upgrade, said another official.
“For a headway of three minutes, we do not need CBTC. It will be needed for the 90-second intervals. The work will happen in due course,” said another official.
Speed
Now, the trains have a maximum speed of 55kmph. Only between Noapara and Dakshineswar, the trains can run at a speed of 80kmph. RITES has conducted a study to reduce the gap between the two trains and increase the speed on the rest of the corridor.
“A proposal has been submitted and is under consideration,” said an official.