Work on raising the height of the Sandhurst road over bridge (ROB) near Charni Road railway station would begin from March.
The height of the bridge is being raised for allowing conversion from 1500-volt Direct Current (DC) to 25000-volt Alternating Current (AC) on the Borivli-Churchgate stretch and thereby improving power supply to trains.
“We want to complete the work of raising the ROB by June before monsoon,” said chief PRO, S Chandrayan of Western Railway (WR).
Currently the height of the ROB stands at 4.4 meters from the tracks. The railway officials will have to obtain a height of at least 4.69 meters for allowing the conversion.
Three pillars support this 2400-ton ROB with one each on the ends and one in between the railway lines.
Officials from WR said that they would increase the height of the bridge placing a pneumatic jack.
“This jack would be placed in a gap between the girder and each of the pillars. Using a remote control, all three jacks would be precisely lifted at the same time so that the bridge doesn’t tilt,” said a senior official on condition of anonymity.
Once the girder (main portion of the ROB above the tracks) is raised, metal frames would be positioned in a way that the gap is filled, and the height is elevated.
The ends of the ROB would then be increased using a new road layer so match the increased height of the girder.
Officials feel the process is difficult as they have to ensure that the gradient (slope of the road) isn’t steep, that the utilities like gas pipelines, electricity and telephone cable going beneath the girder aren’t tampered with and that the ROB does not tilt on either side.