Central Railway faces crucial issues in DC-AC conversion project

Mumbai: One of the most vexing technical issues for the Indian Railways — the conversion of Central Railway’s electrical systems from 1,500-volt Direct Current to 2,500-volt Alternating Current — is now confronted with two essential questions for its train-runners — how the congested suburban system will be run if local trains have a speed limit of only 15 kilometres per hour over nine stretches between Kurla and CST, and how to ensure that no locomotive with height exceeding 4.27 metres ventures into the Kurla-CST section.

Commissioner of Railway Safety Chetan Bakshi has been studying the progress of the conversion for the last two nights, but several CR officials told that these two questions continue to haunt the Rs1,300-crore project which has been in the wings for two years.

“How can we even think of running suburban trains between Kurla and CST at 15kmph? The number of trains run per hour on the suburban system will reduce by 30%. In a crowded system like CR, this is unthinkable,” said a senior CR official.

Talking about the height problem, he added, “Most of the new LHB coaches used in Duronto, Garib Rath etc, are above 4.27 metres, making them out of bounds at CST. Additionally, the motor coaches of the Siemens rakes also exceed this height, making their entry into CST an issue. Numerous diesel locomotives exceed this height because of their chimneys. In short, running trains from CST, one of the country’s largest termini, will be a technical nightmare.”

Bakshi told that the issues have been referred to CR and it is for the CR authorities to come up with a solution. “These are vital safety issues and the conversion can see the light of the day only after a solution is found,” he said.

CR general manager SK Sood did not respond when asked for an inkling when the conversion will take place. Officials said the chances of the conversion getting postponed to after the monsoon is a very real possibility now.

Savings in Energy

CR officials believe the conversion from DC to AC between CST and Thane will save at least Rs100 crore in electricity bills annually. CR runs about 1,660 local services, 410 long-distance trains and 346 freight trains daily. The electricity bill for the year 2013-14 was Rs 1,432 crore. CR trains consumed 1,890 million units of electricity.

CR officials said after the conversion of the Kalyan-Thane section, a saving of 25.8 million units of electricity, equivalent to Rs112.74 crore, was achieved for the financial year ending March 2014.


A single system as opposed to the duality of AC and DC will minimise train failures.

Long-distance trains will save time as they don’t have to switch from DC to AC while exiting CR’s Mumbai network.

AC will integrate CR’s Mumbai division with the rest of the Indian Railway network. Currently, the Thane-CST section is a DC island in the vast national railway network.

Lower maintenance of overhead wires and other structures will be required.