Aluminium third rail installation in India's first Metro network promises major energy and cost savings

Kolkata Metro, India's oldest metro network, is transforming significantly to enhance its services and overall efficiency. Metro Railway has laid out comprehensive plans to upgrade its infrastructure and assets as part of an ambitious modernisation initiative. This initiative is set to substantially improve the commercial operations of Kolkata's rapid transit system, promising a more reliable and advanced commuting experience for its passengers. The changes will mark a new era for the Metro, aligning it with global standards and reinforcing its pivotal role in the city's public transportation landscape.

India's first Metro system is upgrading its steel third rail to aluminium third rail, aiming to reduce energy loss by around 84 per cent. This change, occurring after 38 years, will save INR 1 crore per year for each kilometre of track. The highly conductive aluminium third rail, featuring a stainless-steel top, is being installed on the Dum Dum to Mahanayak Uttam Kumar section of the North-South Metro (Blue Line).

The Metro Railway has given the contract to a German company renowned for its extensive experience in manufacturing and replacing Third Rails for over 20 world-class Metros. The replacement project is scheduled for completion within two years. Aluminium third rails have previously been successfully installed on the East-West Metro (Green Line) and the Joka-Taratala stretch of the Purple Line. This technology will also be implemented across all future corridors of the Kolkata Metro.

Kolkata Metro's third rail replacement will follow in the footsteps of Singapore, London, Moscow, Berlin, Munich, and Istanbul Metros, where a similar second rail replacement has been completed successfully, with metro services as seamless as ever.

The aluminium third rail offers superior electrical conductivity, significantly reducing system voltage drops and subsequent energy losses. This reduced voltage drop enhances the acceleration of running Metros, enabling faster trip completion times and allowing Metro services to operate at shorter intervals during peak hours. Consequently, Metro operations will become more efficient. This new system will save substantial energy, helping Kolkata Metro lower operational costs. The entire replacement cost of the third rail is expected to be recouped within three years. The aluminium third rail will also cut carbon emissions by 50,000 tonnes over its lifetime.

Moreover, the aluminium third rail requires less maintenance and is highly reliable and stable. This replacement will be particularly beneficial in Kolkata's hot and humid climate. Less heat will be generated inside the tunnels during contact between the Third Rail Current Collector (TRCC) and the Third Rail. Welding will no longer be necessary for maintenance work as two rails can be joined using a splice joint, contributing to better air quality inside the tunnels.