The Centre has approved projects worth Rs 895.3 crore to significantly upgrade Kolkata's rail network, focusing on the North-South Metro infrastructure and the reconstruction of an ageing railway bridge. Of the total fund, Rs 671.7 crore has been allocated for the Blue Line enhancement, while Rs 223.5 crore is earmarked to rebuild the railway bridge over the Damodar River under the South Eastern Railway.
Blue Line upgrade to boost frequency
The Blue Line enhancement is expected to greatly benefit commuters who have long demanded trains at shorter intervals. Currently, around 6 lakh passengers travel on the Blue Line daily. With the sanctioned upgrade, the corridor will be capable of operating a 2.5-minute headway, reducing waiting times and easing peak-hour crowding. A Metro Railway official stated that the 41-year-old Blue Line was originally designed for a five-minute gap, but rising demand necessitates higher frequency.
Key components of the upgrade
To enable shorter intervals, the network requires several critical improvements:
- Installation of a traction substation at each station
- Replacement of the steel third rail with an aluminium one
- Upgrade of the signalling system to the communication-based train control system (CBTC)
- Increase of maximum train speed
The power system overhaul includes seven new traction substations worth Rs 291 crore, augmentation and upgrade of auxiliary substations (ASS) and traction substations (TSS), power system upgrade from 11 kV to 33 kV across key stretches, strengthening of power supply between Esplanade and New Garia, and upgrade for elevated sections between Netaji and Kavi Subhas stations.
Rebuilding the Kavi Subhas station
The Blue Line suffered a major setback in July 2025 when the southern terminal, Kavi Subhas station, was closed after cracks appeared in one of its platforms. Since then, the corridor has been operating till the second-last southern station, Shahid Khudiram. Work to rebuild the terminal station is about to begin.
Addressing capacity and maintenance challenges
The existing substations and equipment are reaching capacity limits and face maintenance challenges due to non-availability of spare parts. The new system will ensure reliable power supply and reduce disruptions. The steel third rail is being replaced with aluminium in phases, as aluminium is a better conductor of electricity. This will reduce system voltage drops and consequent energy loss, enabling faster train acceleration. The second phase of this work, nearing completion, will cover most of the underground section. The third phase will cover the elevated section between Tollygunge and New Garia.
Signalling upgrade for higher speed
For a 90-second headway, the carrier needs the CBTC system and increased maximum speed. Currently, the Blue Line operates with the train protection and warning system (TPWS). It will be augmented to the more advanced CBTC system, where a train picks up signals from the tracks and becomes a moving block. Metro trains now run at a maximum speed of 55 kmph, except between Noapara and Dakshineswar where speeds can reach 80 kmph. Plans are underway to reduce the gap between trains and increase speed on the rest of the corridor.
