Conversion of the OHE section from DC to AC, CR will run on AC by 2011

Masjid Bridge To Go First, Other To Follow
Mumbai : Central Railway's DC-AC conversion plans have picked up pace and it's not just the old masjid road overbridge that has come in the way of its development plans in the city. Three road overbridges (ROBs) on the Matunga-Sion-Kurla stretch and five foot-overbridges (FOBs) between Kalyan and CST are posing a challenge to the railway authorities.
K K Sharma, chief administrative officer (construction), CR, said, "Five FOBs would need to be dismantled in connection with the DC-AC conversion and tenders for the same have been floated for consultancy and execution.''
Central Railway (CR) plans to bring down the ROB at the northern end of Masjid station during a 48-hour mega block, which will start after the last train leaves CST on August 14. It will facilitate not only conversion of the section from DC to AC, but also extension of the Main line platform to accommodate 12-car rakes and make room for a seventh track.
The DC-AC conversion may also result in three ROBs along the Matunga-Sion-Kurla stretch being removed. However, since the conversion is being carried out in phases, officials say the three ROBs need not immediately be demolished. CR, is also exploring several options to see if the work can be carried out without razing the bridges.
One option CR is looking at is keeping the section under the bridges "neutral''- in other words, have no current flow under the bridges. For AC-powered trains, a clearance of over 6 m is required between the tracks and bridges. "As span of the bridges is only 15 m, movement of trains will not be affected even if a pantograph is not drawing current as AC emits 25,000 volts,'' a senior official said. Nine-car rakes have three pantographs each while a fourth one is added to 12-car coaches.
Another option before CR is using insulators around the overhead wire so that the 6-m clearance is reduced and the bridges are saved. Officials are also looking at increasing the height of the bridges using jacks, but this may not be feasible as the possibility of material failure is high.
Senior CR officials also say lowering the level of tracks to maintain the 6-metre clearance is out of the question as these low-lying areas are prone to heavy waterlogging.
Trains running on AC current will not only be faster, the traction will also allow more services to be run, say officials. Under MUTP-I, DC-AC conversion on the stretch between Kalyan and Kasara has been completed while work on the section from Karjat to Kalyan is on and is expected to be completed by December-end. MUTP-II involves the stretch between CST and Thane; with this, the entire suburban section of CR will run on AC by 2011.