Kolkata, Jun 22 (PTI) The Kolkata metro railway has started using a sustainable braking technology in its rakes, as part of its quest to reduce carbon emissions and save energy costs, an official said on Sunday.

All the new rakes that are being introduced in the city’s rapid transit system feature ‘Regenerative Braking’, he said.

“The technology allows a train's electric motors to operate in reverse (like a generator) during braking, leading to conversion of the train’s kinetic energy back into electrical energy, rather than wasting it in the form of heating of wheels or brake shoes,” a Metro Railway Kolkata spokesperson said.

At present, the Kolkata metro railway operates 37 rakes with regenerative braking features.

“The total energy regenerated in the year 2024-25 – by usage of the system in 37 rakes – has been 1.08 crore units, which have saved around Rs 8.2 crore in energy cost,” he said.

Regenerative braking has reduced carbon emissions by 13,500 tonnes in the previous financial year, the official said.

In a study conducted by Metro Railway Kolkata, it has been observed that 17-20 per cent regeneration of electricity is possible, he said.

“This is a step forward for saving energy and reducing the use of fossil fuel. Urban metro systems like those in London, Tokyo and New York also use regenerative braking,” the spokesperson said.

“The unique advanced 'Regenerative Braking System' technology reduces wear and tear of brake, wheel, brake disc as well as maintenance costs,” he said.

In another green initiative, Metro Railway Kolkata has taken up the work of setting up a 4-MW ‘Advanced Chemical Cell (ACC)’ battery storage system, “which is the first of its kind in Indian Railways”.

The batteries have arrived and the system is expected to be operational in the middle of July, 2025, he added. PTI SUS RBT

Regenerative braking adoption enables energy recovery and reduced carbon emissions in urban metro operations and lower maintenance costs. Kolkata Metro Railway has implemented Regenerative Braking across 37 rakes to convert braking kinetic energy into electrical energy for reuse, achieving an observed 17-20% regeneration rate, reported energy and cost savings in 2024-25, reduced brake and wheel wear, and a quantified reduction in carbon emissions; it is also installing a 4-MW Advanced Chemical Cell (ACC) battery storage system to store regenerated energy.