Metro commuters have been fuming over disruptions in services for the second day in a row on Wednesday owing to glitches in the signalling system.
From 8.30 a.m. till 10.30 a.m., trains stopped every now and then and ran at a reduced speed of nearly 25 kmph. This is the third time in a week that services have been hit by issues in signalling system.
How does a Metro Rail run and what caused this failure?
Every morning, an employee of Chennai Metro Rail feeds the information of the entire schedule of trains into a special software in the Operations Control Centre (where movements of all trains and other systems are monitored and controlled). The software in turn sends the respective information to each train (the train has various details including its schedule, the frequency and speed.)
The signalling system in the Chennai Metro Rail network has an important component called Automatic Train Supervision (ATS), which tells a train what its next stop is and monitors its movement, sources said. All recent disruptions in Metro services occurred due to a technical glitch in the ATS; when the ATS failed, usually there are two backup systems to run the trains but these two also failed, thereby leading to disruptions in the signalling system and hence, the trains came to halt immediately, sources said. Now, the trains — which is usually operated in a completely or semi automatic mode — have to be manually operated by the driver or train operator, sources added.
Manual operation
“The train that has stopped will not be operated manually instantly; the staff in OCC have to communicate to every train operator and ask them to drive. But when a train runs manually, the system will allow the train operator to run it only up to a maximum of 25 kmph for safey reasons,” a source said.
This is why for two days now, the trains stopped, ran at reduced speeds and had consequential delays.
Officials said there were trying to find out why the ATS had a glitch.
Siemens, which provides the signalling system said, it is providing all necessary support to Chennai Metro Rail Limited (CMRL) to ensure that there are no interruptions and delays to the train operations.
“Siemens has provided a signaling system to CMRL that is capable of running in fully-automatic mode for train operations, as well as a back-up system with human intervention. This system allows CMRL to operate its trains as per the defined timetables. The CMRL staff is also trained by Siemens on how to operate the system in such scenarios,” an official said.
