Stone bridges stand in the way of faster train commute

Forty lakh commuters who travel via local trains could soon be reaching their destinations faster, but for some obstacles, in the form of the old road over-bridges that are built above the tracks.

Obstacle course: There are at least five such ROBs, including the ones at Sandhurst Road, Byculla, Chinchpokli, Currey Road and Dadar that date back to the British era. file pic

Central Railway (CR) is converting the overhead lines, which run on 1,500-volt DC, to 25,000V AC. This would lead to faster travel for commuters and CR would also save on electricity. But, one will have to wait a little longer, since CR hasn't yet figured out how to carry out the conversion for the overhead wires under the old road over-bridges (ROBs) in the island city (up to Sion). There are at least five such ROBs, including the ones at Sandhurst Road, Byculla, Chinchpokli, Currey Road and Dadar that date back to the British era.

Sources at CR said that after the upgrading is done, a minimum distance of 4.69 metres has to be maintained between the railway tracks and the bridge. Usually, during the process of conversion to AC lines, bridges are lifted hydraulically and work is carried out on the wires. But, since these bridges are made of stone, they cannot be lifted. "We're having discussions with the Railway Board on how to go about the conversion process, apart from our internal meetings," said a senior CR official.

"Ideally, we are looking at the process of ‘condonation'. In this process, the cables below the bridge will be double insulated for safety. We may also look at lowering the level of tracks to carry out the conversion process," added the official. On September 13, Kul Bhushan, a member of the Railway Board (Electrical), met the CR authorities to have a discussion on these issues.

The authorities have some time to mull over the problem of stone ROBs, since the process of conversion to AC lines is stuck at Parsik Tunnel, near Thane. According to authorities, they're facing a similar problem - the distance between the tunnel and the overhead wires is too less.

The lines from Karjat/Kasara to Kalyan Junction have been converted to 25,000-volt AC.

Once the conversion from Kalyan Junction to Thane is completed, the project will move ahead to the Thane-Kurla/LTT lines. Only after these lines are completed will the conversion start from Kurla - CST, the region in which all of the stone ROBs are built.

According to officials, the entire process of conversion, up to CST, will take at least another year.

Mar 2013
Orignal deadline

May 2013
Reviesd deadline

Sept 2013
Latest deadline

Rs 796 cr
Project cost

Why convert to AC?
Once the process of conversion to 25,000-volt AC lines is done, CR will be able to add more services. This is because the maximum speed for trains on the current 1,500-volt DC line is 80 kmph while the AC-compatible
rakes can clock up to 100 kmph

62
Number of CR trains that run on DC

59
Number of CR trains that run on AC

4
Number of trains that run purely on ACu00a0