Kolkata Metro aluminium third rail upgrade: The Kolkata Metro railway has completed the Aluminium third rail upgrade across the entire underground section of its Blue Line. With this upgrade, the 40-year-old conventional Steel third rail system has been replaced with an advanced high-conductivity Aluminium third rail system. In 2012, the Ministry of Railways decided that all new Corridors of Kolkata Metro will be built with Aluminium third rail.
Manufactured by Steel Authority of India Limited (SAIL), the Steel third rail system had been supplying power to metro rakes for more than four decades. However, with advancements in technology, the once-modern system of the 1980s had gradually become outdated and energy inefficient in today’s era of green energy initiatives.
According to Kolkata Metro Railway, this major technological upgrade is a significant step towards modernising the traction infrastructure and achieving the faster train operations, i.e. targeted 150-second train headway in future operations.
In a statement, the Metro Railway said: “Aluminium’s electrical conductivity is 38 million siemens per meter whereas Steel has value of 6 million siemens per meter. This physical characteristic of Aluminium is a simple reason for lesser voltage drops and lesser energy losses compared to Steel third rail. Apart from lesser loss, nearly no voltage drop in the third rail will help to achieve faster acceleration of train and reducing headway of running Metros.”
The underground section of Kolkata Metro Blue Line stretches from Noapara to Dum Dum and again from Belgachia to Mahanayak Uttar Kumar station.
Kolkata Metro further said that the aluminium third rail system is expected to reduce carbon emissions by nearly 50,000 tonnes over its lifetime. The metro authority also stated that the new system will reduce the heat load on air-conditioning systems inside tunnels, as aluminium generates less heat due to its lower resistance compared to steel.
“The initiative is expected to generate substantial environmental benefits, including an estimated reduction of nearly 50,000 tonnes of carbon emissions over its lifecycle. The upgradation forms part of Metro Railway Kolkata’s broader modernization roadmap, which includes implementation of advanced signalling systems to support higher-frequency operations, improved reliability and enhanced passenger carrying capacity on India’s first metro corridor” the Kolkata Metro said.