Kolkata Metro has completed the upgrade of the aluminium third rail on the underground Blue Line to enable faster train operations and improved energy performance. The project covers the underground stretches from Noapara to Dum Dum and from Belgachia to Mahanayak Uttar Kumar station. The authority described the work as a significant step in the modernisation of traction infrastructure.

Metro Railway Kolkata said the change is intended to support a targeted 150-second train headway in future operations as part of timetable optimisation. Officials highlighted that aluminium has an electrical conductivity of 38 million (mn) siemens per metre compared with six mn siemens per metre for steel, a contrast that reduces voltage drops and energy losses along the live rail. The reduced electrical loss is expected to aid faster acceleration of trains and permit shorter intervals between services.

The authority noted that the aluminium system will cut heat generation owing to lower resistance, reducing the cooling burden on tunnel air-conditioning systems and improving environmental control within underground sections. It estimated that the upgrade will reduce carbon emissions by nearly 50,000 tonnes over the system lifecycle, equivalent to 50,000 t. The authority framed these outcomes as benefits for both operational efficiency and long-term sustainability.

The third rail replacement forms part of a broader modernisation roadmap that includes advanced signalling to enable higher-frequency operations, improved reliability and enhanced passenger carrying capacity on India’s first metro corridor. Officials indicated that combining infrastructure upgrades with signalling improvements will permit more intensive use of existing track capacity without extensive civil works. They expect reliability gains to translate into improved service regularity and passenger experience.

Further monitoring and phased implementation of higher-frequency services will determine the practical gains in headway reduction and energy savings. The metro authority said ongoing assessment will guide future steps on scheduling and system optimisation.