Metro glitches may lead to CBTC tweak

Tuesday night’s glitch in the Hyderabad Metro Rail trains on Corridor One - L.B. Nagar to Miyapur line — when a train came to a halt and did not move for quite sometime due to a ‘signalling problem’ — has authorities racking their brains.

There have also been passenger complaints about sudden jerks, doors opening and unscheduled stoppages on various occasions.

Mulling solutions

Metro rail authorities are now wondering if the solution is to make the systems more robust by giving an additional coat of paint or covering sensitive equipment, or to straightaway go for tweaking of the actual software support system of the Communication Based Train Control (CBTC) provided by Thales.

What had happened on Tuesday night and in a few earlier instances is that once a signalling issue occurs in a particular section, the entire system goes into a ‘fail safe’ mode, shutting down everything with red signals flashing through the entire section.

Automatic shutdown

It then forces the engineers to manually switch off the system after taking care of track clearance and safety. “If there are 100 parameters and CBTC is not happy with even one, it will shut the system,” they explained.

In the interregnum, trains will have to go slow at about 25 kmph and they get bunched leading to a cascading effect. Since air pollution and other conditions are not going to vanish any time soon, metro rail authorities think the only option left is to make the “highly sophisticated CBTC and other systems more suitable to rugged Indian conditions and pollution levels”.

Manual disruptions

The sudden brakes and halt during transit even as it leaves a station at times is because passengers are “rushing in even as doors are closing or there is an obstacle in the form of a bag or arm/leg preventing doors from closing automatically when the CBTC gets into action again,” they said.

“This is an issue plaguing all metros in India including the Delhi metro because of the peculiar conditions like extreme dust in the air for instance. But we are very much concerned over the development and looking at various means to tackle it,” said HMR Managing Director N.V.S. Reddy.