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METRO RAILWAY REPLACED STEEL THIRD RAIL BY HIGHLY CONDUCTIVE ALUMINUM THIRD RAIL AT MAIDAN
Kolkata, 15.09.2024
On 14.09.2024 night Metro Railway has successfully replaced the Steel third rail at Maidan siding. Approximately 200- meter long rail has been replaced. Prior to this, the Steel third rail at Girish Park siding was replaced in the last week.
Replacement of third rail at Maidan siding was more challenging compared to Girish Park as it has been situated in a curvature and highly conductive Aluminum third rail had to match the exact curvature of rail to ensure proper power connection between third rail and rake.Metro Railway has recently started replacement of Steel-made current conducting third rail with Aluminum third rail in the North-South Metro (Blue Line). The replacement work of Steel third rail by highly conductive Aluminum third rail at Girish Park siding was earlier completed on 07.09.2024.
It is to be noted that this replacement work is extremely critical as delay in completion of this work at night may lead to traffic disruption in the next morning. So, all steps are monitored critically and after detailed minute to minute planning, back up planning and fall back strategy in place the work is getting executed.
For this work, at first new pedestals are made of appropriate height with best material available in the market (M65 pre mix concrete to avoid any adulteration and quality compromise).Then all materials like third rail components and shroud boards are brought to the sites and kept in safe location.One day before the scheduled work, the shroud boards of existing rails are removed. On the execution day, after the commercial hours, existing steel rails are cut at marked locations and dismantled. After that the race against time begins. New GRP (Glass Reinforced Plastic) insulators are placed in these pedestals. Then the new highly conductive Aluminum third rail is placed on these insulators adjusting height and distance of rails. After that interconnection between existing power supply system is done with cables. After all adjustment of mid-point anchor, expansion joints and cable connectors, one final checking of tightness of all fasteners are done. Finally, the shroud boards are placed on the rail.
On 14.09.2024 the entire work completed before 05:00 am boosting the confidence of the team doing this work.Metro Railway deputed approximately 50 staff and supervisors led by Deputy Chief Electrical Engineer/ Maintenance / Coordination Shri Sumit Kayal for execution of this work last night. The work was completed well before commercial service on Sunday morning. With the experience gathered from the Girish Park and Maidan sidings, Metro Railway will start replacing the Steel third rail by the Aluminum third rail on the main line shortly.
Preparatory work of pedestal base foundations has already been started in main line.This highly conductive Aluminum third rail has the capacity to reduce the system voltage drops and subsequent energy losses, thanks to its superior electrical conductivity. This less voltage drop in the third rail will help to achieve faster acceleration in the running Metros. That will be an improvement in the efficiency of Metro operations. In this new system huge amount of energy will be saved which will in turn help Kolkata Metro to reduce its operational cost. As a result, the entire expenses for replacing this third rail could be realized within three years by saving this operational cost.
Additionally, the Aluminium third rail will reduce carbon emission by 50000 tons in its lifetime.Apart from this, Aluminum third rail will require less maintenance and will be highly reliable and stable. In a hot and humid city like Kolkata this replacement will be very much beneficial and inside the tunnels lesser heat will be generated during the time of contact of Third Rail Current Collector (TRCC) with this third rail. For maintenance work the new third rail will not require any welding as two such rails can be joined with the help of splice joint. It will help to maintain the air quality inside the tunnels.
By Kausik Mitra,Chief Public Relations Officer
