Metro Railway Kolkata has completed the replacement of the conventional steel third rail with a high-conductivity aluminum third rail across the entire underground section of its Blue Line, marking a major traction infrastructure upgrade on India’s first metro corridor.
In a statement on Thursday, 28 May, the Ministry of Railways said the upgrade is aimed at improving electrical performance, reducing energy loss and supporting higher-frequency train operations in the future.
The modernization is also linked to Metro Railway Kolkata’s long-term plan to achieve a 150-second train headway, which would allow trains to run at shorter intervals and increase passenger carrying capacity on the busy North-South corridor.
According to the ministry, the new aluminum third rail offers better electrical conductivity than the earlier steel system.
It is expected to reduce transmission losses, limit voltage drop and improve energy efficiency during train operations.
The upgrade is also expected to deliver environmental gains.
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The ministry said the aluminum third rail system is estimated to reduce nearly 50,000 tonnes of carbon emissions over its lifecycle.
The completed work covers the underground section of the Blue Line, which forms the core of Kolkata Metro’s original North-South corridor.
The line has seen rising commuter demand over the years and is being progressively upgraded with modern systems to improve reliability and operational efficiency.
The third rail supplies traction power to metro trains.
Replacing steel with high-conductivity aluminum is intended to improve power delivery and reduce energy wastage, particularly on high-frequency metro operations where stable traction supply is critical.
The ministry said the third rail upgrade forms part of Metro Railway Kolkata’s broader modernization roadmap.
This also includes advanced signalling systems needed to support higher train frequency, improved reliability and greater passenger capacity.
