AMAR METRO
KOLKATA
PRESS RELEASE
REPLACEMENT OF STEEL THIRD RAIL WITH ALUMINIUM THIRD RAIL IN BLUE LINE GOING on
Kolkata, Date:11.06.2025
Metro Railway, Kolkata, country's first Metro, has undertaken an ambitious plan of replacing its Steel third rail with Aluminium third rail in Blue Line and gradually has been progressing with the work. This project has been undertaken with an objective to improve Metro services on Blue Line. Upon completing 40 glorious years of service to the Nation, this project aims to put Metro Railway, Kolkata in the league of London, Munich, Moscow and Istanbul Metros.
Metro officers and staff have been working in tandem after the commercial hours to execute this project within the deadline. Already 13.5-Km long Steel third rail has been replaced with Aluminium third rail on UP and DN lines between Shyambazar and Rabindra Sadan stations. According to this mega plan, a total of 38-Km Steel third rail will be replaced by Aluminium third rail between Noapara to Mahanayak Uttam Kumar stations by December, 2025. After that the Steel third rail replacement work will be taken up from Mahanayak Uttam Kumar to Kavi Subhash stations, it is expected to be over by December, 2026. once that is completed, Metro will be able to save 6.6 crore units of energy every year leading to savings of Rs. 50 crore yearly.
Steel third rail, manufactured by SAIL, a central government PSU, has been providing power to rakes successfully for 40 long years in the Metro. With the evolution of technology, advanced systems of the 80’s are becoming irrelevant and energy inefficient in today’s era driven by green technologies. Keeping in mind the above facts, the Ministry of Railways has decided in 2012 that all new Metro Corridors will be built with Aluminium third rail. Accordingly, all Corridors of Metro Railway, except 40-year old Blue Line are having Aluminium third rails.
After implementing Aluminium third rail in Green Field Projects, Ministry of Railways has decided to replace Steel third rail of Blue Line. Accordingly, open tenders were floated and contracts were awarded to Indian subsidiary of REHAU Group Company who assured that more than 60% of contract value will be sourced from India and remaining from Germany.
To implement this project, detailed engineering works, manufacturing of components and site preparation are being done in phases. Considering the Government of India’s green initiative in mind General Manager Shri P Uday Kumar Reddy has emphasized to implement the project on a fast-track basis. GM has been regularly monitoring the progress of this work. First phase materials were received in the first week of August, 2024.
The replacement work has been extremely critical and demanding as delay in completion of work within the non-commercial hours, might lead to traffic disruption in the next morning. So, all steps are being monitored critically and with minute to minute planning, back up planning and fallback strategy in place the work is getting executed. New pedestals with appropriate height are being constructed with M65 pre mix concrete which is generally used in making piers of Metro viaduct so that required strength is obtained within a day of erection. All materials like third rail components and shroud boards are brought to the sites and kept in a safe location and old shroud boards of existing rails are removed. on the execution night, existing Steel rails are dismantled and highly conductive Aluminium third rails are placed on New GRP (Glass Reinforced Plastic) insulators. The height and distance of the rails are also adjusted. Interconnection between existing power supply systems is done with cables. After the adjustments of mid-point anchor, height and distance of the rails, expansion joints and cable connectors, tightness of all fasteners, the shroud boards are placed on the rail. one of the main features of this shroud board is it is fire resistant with a low smoke generator in case of fire.
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 helps to attain lesser voltage drops and lesser energy losses compared to Steel third rail. Apart from nearly no voltage drop, the Aluminium third rail helps to achieve faster acceleration of the train and reduce the head way of running Metros. As a result, the entire additional expenses for replacing this third rail will be realized within five years through savings in operational cost. Additionally, Aluminium third rail will reduce carbon emission by 83,000 tons in its lifetime.
Apart from this, Aluminium third rail will require less maintenance and have more codal life because of absence of corrosion. Aluminium weighs 169 pound /cubic foot and steel weighs 490 pound / cubic foot. So, manpower required to handle Aluminium third rail is much lesser. New third rail will not require any welding as two Aluminium rails can be joined with the help of splice joint. It will help to maintain the air quality inside the tunnels and shall have no risk of cable fire while welding.
Aluminium third rail will also reduce heat load to the AC system as inside the tunnel lesser heat will be generated for the low resistance value of the Aluminium compared to Steel.
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