Kolkata Metro joins elite club of London, Moscow, Munich metros using this system

New Delhi: Kolkata Metro Railway is all set to embark on a groundbreaking transformation as it transitions from its conventional steel Third Rail system to a cutting-edge composite aluminium third rail system, aligning itself with the exclusive league of elite global metros in cities like London, Moscow, Berlin, Munich and Istanbul, which have already embraced this innovative technology, the ministry of railways said.

For nearly four decades, Kolkata Metro Railway has relied on the steel Third Rail to supply power to its rolling stock at 750V DC. The Third Rail Current Collector (TRCC), predominantly constructed from steel, has been the backbone of this lifeline service. Now, in a forward-thinking move, Kolkata Metro Railway has opted for the advanced Aluminium Third Rail system.

This transition will be implemented across all upcoming metro corridors currently under construction, alongside retrofits in existing corridors currently equipped with steel Third Rails. The conversion plan will be executed in three distinct phases.

According to the ministry, in the initial phase, Kolkata Metro Railway will commence the replacement process of the Third Rail along the Dumdum to Shyambazar section. The second phase will encompass the Shyambazar to Central and JD Park to Tollygunge sections. Finally, in the third phase, the transition will be extended from Mahanayak Uttam Kumar (Tollygunge) to Kavi Subhash (New Garia).

The comprehensive project will result in the replacement of a total of 35 RKm (route km) mainline steel Third Rails, facilitating a seamless transition to the advanced Aluminium Third Rail system.

The advantages of the aluminium composite third rail over its steel counterpart are significant. Firstly, it reduces resistive current loss due to its lower resistance, resulting in improved traction voltage levels. Secondly, this transition promises capital investment savings, with one less Traction Substation required for a 10-km corridor, translating to an estimated savings of approximately ₹210 crores for a 35-km metro corridor. Thirdly, it enhances operational efficiency by allowing for faster acceleration.

Furthermore, the Aluminium Composite Third Rail reduces maintenance and life cycle costs by eliminating the need for frequent repainting and lowering the risk of rusting. It also promises improved train operations, ultimately leading to better headway between trains.

Most importantly, this shift to Aluminium Composite Third Rail aligns with sustainable goals, as it is projected to save an estimated 6.7 million units of energy annually, which will significantly reduce the metro's carbon footprint.