AMAR METRO
KOLKATA
PRESS RELEASE
NEW ALUMINIUM THIRD RAIL INSTALLED AT MAHATMA GANDHI ROAD METRO STATION on 30TH NOVEMBER/ 1ST DECEMBER 2024 NIGHT
Kolkata, 01.12.2024:
At least fourteen countries of Asia use the third rail system for providing DC traction power to its rake. Metro Railway, Kolkata has been the fifth in Asia to commission Metro Railway. Steel third rail manufactured by SAIL, a central government PSU, has been providing power to rakes successfully for 40 long years. With the evolution of technology, advanced system of 80’s has been becoming irrelevant and energy inefficient in today’s era of green energy. Keeping the above fact in mind, the Ministry of Railways decided in 2012 that all new Corridors will be built with Aluminium third rail. Accordingly, all new lines of Metro Railway, Kolkata except 40-year old Blue Line are now having Aluminium third rail.
After implementation of the Aluminium third rail in the Green Field Project, the Ministry of Railways has decided to replace the steel third rail of Blue Line by Aluminium one and sanctioned Rs.113 Cr in Financial Year 2022-23 for replacing 2X17 km i.e. 34 km steel rail of entire underground section 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 shall be sourced from India and remaining from Germany.
All of us are aware that on 07.09.24 and 15.09.24, Metro Railway has replaced successfully steel third rail of its two yard lines at Girish Park and Maidan by Aluminium third rail brought from Germany with remaining components procured from India engaging local work forces under the supervision of Metro Railway Engineers headed by Shri Sumit Kayal, a Joint Director Level officer. After successful commissioning of yard line's third line, team headed by Shri Sumit Kayal took the real challenge on the night of 30.11. 24 - 01.12.24 to replace SAIL manufactured steel third rail by Aluminium third rail of the main line from Girish Park to Central stations, including Mahatma Gandhi Road station.
Challenge before the team was to complete the section 100% perfectly so that commercial service would not get affected this morning.
Replacement work is as good as commissioning of new system with addition to safe removal of old system.The section replaced is approximately 700 meters in length. The main challenge before the team was to ensure alignment, height and distance perfectly within the 5 hours of non-commercial window made available to them. Also, to ensure passenger safety, protective shroud cover over newly installed third rail was installed in the platform area. Till date approximately 1800 meters steel third rail have been replaced by Aluminum third rail out of which 1400 meters in main line and 400 meters in Y-sidings. The entire work has been planned to be completed before 15th August 2025. Detailed engineering, manufacturing of components and site preparation were done in phases by Sri Sumit Kayal and Sri Abhishek Sinha of Metro Railway Kolkata. Considering the Government of India’s green initiative in mind, General Manager Sri P Uday Kumar Reddy has emphasized to implement the project on fast-track basis.The first phase of materials were received in the first week of August, 2024 and second lot of third rail has already been inspected.
The replacement work is extremely critical and demanding as delay in completion of every day’s work may lead to traffic disruption in the morning. So, all steps are monitored critically and after detailed minute to minute planning, back up planning and fallback strategy in place the work has been executed. New pedestals are made of appropriate height with M65 pre mix concrete which is 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 were brought to site and kept in safe location on last Friday night and old shroud board of existing rails have been removed. on the execution night, i.e.30th November-1st December, existing steel rails were cut at marked locations and dismantled. After that it was a race against time. New GRP (Glass Reinforced Plastic) insulators were placed on pedestals of M65 concrete abandoning old porcelain insulator and its pedestals. Then the new highly conductive Aluminium third rail was placed on the insulators. Height and distance of rails were adjusted. Interconnection between existing power supply system was done with cables. After all adjustment of mid-point anchor, expansion joints and cable connectors, one final checking of tightness of all fasteners was done. Finally, the shroud boards were placed on the rail. This shroud board is fire resistant with low smoke generation in case of fire. on 01.12.24 the entire operation was completed 1 hour before the sanctioned block. Metro Railway deputed approximately 40 staff and supervisor led by Sri Sumit Kayal and his Senior Section Engineer Sri Abhishek Sinha.
Aluminum’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. As a result, the entire additional expenses for replacing this third rail shall be realized within five years for 150 sec frequencies through saving in operational cost. Additionally Aluminium third rail shall reduce carbon emission by 50,000 tons in its lifetime.
Apart from this, Aluminum third rail will require less maintenance and have more codal life. Aluminum 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 aluminum 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 shall reduce heat load to AC system as inside the tunnel lesser heat will be generated for low resistance value of the Aluminum compared to Steel.
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