Mumbai's first AC train too tall for British-era bridges

Jul 22, 2016, 08:30 IST | Shashank Rao

CR can no longer carry out the trial run on the CST line, as only now have the officials realised that the new rake is too tall to pass under some of the older bridges towards south Mumbai

Mumbai’s first air-conditioned local has been cooling its heels at the Kurla carshed for over three months now, as Central Railway authorities worked to fix all technical glitches before taking it out for trial runs, which were initially supposed to take place in May. Ironically, the officials have missed a major problem that has been staring them in the face all along — at almost 4.3 metres tall, the new AC rake is simply too big to pass under some of the city’s bridges without posing grave danger.

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It didn’t strike CR officials until last week that adding the AC units on top of the coaches meant that the rake would be too tall to pass under the bridges
It didn’t strike CR officials until last week that adding the AC units on top of the coaches meant that the rake would be too tall to pass under the bridges

It is particularly bridges towards south Mumbai that pose a problem, as they were built over a century ago and hang lower than most bridges – too low to accommodate the cooling units on top of the AC coaches.

Cutting it too close
While the rake itself is of standard size, it’s the addition of the half-foot AC units that will leave just 30-50 mm (or 3-5 cm) between the top of the train and the base of the bridge. Officials said this would be cutting it too close, and there is a chance that the overhead cooling units could come in contact with low-hanging ROBs and FOBs.

The Currey Road ROB is one of the problem sections, where the gap between the base of the bridge and the top of the AC train could be as little as 3 cm. Pic/Satej Shinde
The Currey Road ROB is one of the problem sections, where the gap between the base of the bridge and the top of the AC train could be as little as 3 cm. Pic/Satej Shinde

And while this might seem like an obvious problem to most people, CR officials only realised the goof-up in the past week, when they finally began to consider starting trial runs on the main Central line. That’s when they realised that they would not be able to run the train between CST-Kurla, because, there are at least four bridges that are too low on this stretch (see ‘Problem bridges’).

Read Story: Mumbai: Major glitch in AC train puts Central Railway in the hot seat

Apart from the old bridges, even the height of the tracks has been raised in certain sections of the CST-Kurla route. Although this proved to be useful in preventing waterlogging on tracks this monsoon, the move has further reduced the clearance gap for trains.

No AC for SoBo
“The officials from the Integral Coach Factory have been informed and they will chip off the excess metal in the next AC rake that will be manufactured,” said a CR official. However, nothing can be done about the rake that is already here, and chances are that it will ply towards CST at all. Instead, CR will likely conduct the trial runs on the Kalyan-Kasara/Karjat route or on the Trans-harbour section between Thane and Vashi.

10 days to go
CR has already missed the deadline for trial runs twice. It was initially supposed to start the trial from May 16, but due to several technical glitches, the date was pushed to June 30. Now that all technical glitches have been fixed, the authorities hope to take the AC train out for its first ride by the end of this month. “The problem with the height of the AC train is being looked into. We hope to carry out the first trial run by July 31, said Narendra Patil, chief PRO, Central Railway.

Trial and error
This AC local has seen its share problems in the past few months, but all these issues have been rectified:

>> The AC, automatic doors and train operations were not synchronised 
>> During static trials, it was seen that emergency brakes weren’t working and doors weren’t opening 
>> Initially, the high-power AC units — all 360 tonnes — were vibrating heavily and overcooling the coaches to a frigid 16 degrees instead of the preferred 22-24° Celsius

Safety measures
>> If the AC switches off in case of technical failure, the trains blowers will switch on and run for up to six hours
>> A second console has been added so both the Guard and the Motorman can operate the doors 
>> The train is also fitted with a red button that will function as the passenger feedback system, so commuters can speak to the motorman or the guard

4.3 m
The height of the AC rake; while the coaches are of standard size, the cooling units add half a foot on top

Rake heights
Siemens – 4,270 mm
Bombardier – 4,257 mm
AC – 4,295 mm

Problem bridges
>> Carnac Road bridge
>> Currey Road bridge 
>> Matunga station FOB
>> Byculla bridge

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