By May end the entire stretch from Thane to CST on the Central Railway (CR) will switch over from 1500 Volt DC(Direct Current) to 25 KV AC(Alternating Current) . This will in turn offer more services on the central line. “We have set a target of May end to convert the entire stretch from Thane to CST to AC current,” remarks S K Sood, General Manager, CR.

 

The switch on the Main line is expected to improve efficiency of services, bring down breakdowns as well as help the railway save around Rs 120 crore per annum from reduced transmission loss and conserve 33% energy.  The railways have already converted the stretch from LTT-Thane from DC to AC, and have been running two types of rakes between Thane and CST which  operate on DC system.

 

The Main line has 75 rakes, 65 of which can run on both AC and DC traction. The remaining 10 rakes are DC-compatible and are used on the CST-Thane section only. “We have to handle with operational problems as DC rakes cannot enter the AC territory. The switch to AC will allow us phase out retro-ffited trains, which are old and so, prone to breakdowns. AC rakes will increase efficiency of the system," an official said. "The railway board has assured supply of enough AC-compatible rakes before we go in for the switchover."

 

 

Advantage of AC traction:

 

Maintenance-related failures will come down as 75 sub-stations are needed to supply power to suburban trains under the DC system,  as compared  to only 11 sub-stations are required for the AC system. The AC system needs lighter overhead wires than that of DC, which has thicker and heavier contact wires and pantographs that are prone to fast wear and tear.