Chennai rains: Failure of signalling system cripples suburban train operations in city

CHENNAI: The South Chennai suburban network was crippled after track circuit-based signalling system failed due to heavy rain since Thursday night. The system helps smooth movement of trains without manual intervention and is key to rail safety as the entire network works automatically.

Thousands of rail commuters of South Chennai suffered on Thursday evening as the number of services in Chennai Beach - Chengalpattu suburban section was reduced. Trains were stopped between Egmore and Tambaram for more than hour.

The torrential rain brought railway tracks at Perungalathur, Tambaram, Nungambakkam, Kodambakkam, Pallavaram, Chromepet and St. Thomas Mount under water on Thursday evening. This led to slow operation of suburban trains and south-bound trains, including Pandiyan, Nellai and Podhigai Expresses upto Chengalpattu.

Later, electrical circuits of three suburban lines at Tambaram also got damaged. Even before railway workers began to fix the damage, the entire track circuit signalling system between Chengalpattu and Chennai Beach failed, railway sources said.

Later, suburban operations were restored amid heavy rain by clearing the signals manually.
The signal failure also disrupted shunting of trains from Gopalsamy Nagar yard to Egmore station, leaving south-bound trains being delayed for more than two hours.

The Tiruchi-bound Rockfort Express scheduled to leave Egmore at 11.30 pm, started at 2.10 am on Friday, while Mangaluru Express left at 1.20 am as against its scheduled time of 11.45 pm. Similarly, Salem Express and Uzhavan Express left after a 90 minute delay. Later, more railway staff were involved to operate suburban trains at slow speed by clearing the signals manually.

On Friday morning, suburban train services which were already delayed from Chengalpattu and Tambaram could not be resumed before 7.00 am. Trains were operated once in 45 minutes at slow speed. Particularly, commuters from Chengalpattu, Perungalathur, Maraimalainagar and Guduvanchery were the worst affected as all the fast locals were operated on suburban lines at slow speed.

Due to waterlogging on tracks between Chengalpattu and Tambaram, trains from southern Tamil nadu, including Kanniyakumari Express, Ananthapuri Express, Pearl City Express and Thiruvananthapuram - Chennai mail, and Salem - Chennai Express were stopped between Villupuram and Chengalpattu for about two hours. The trains were delayed by about three hours when they reached Chennai Egmore.

Similarly, a few train services between Chennai MMC - Gummudipoondi were also running late due to water-logging on tracks. Services returned to normal in the afternoon. A senior railway official said efforts had been taken to ensure smooth operation of suburban trains. Despite failure of the track circuit signal, almost 95 per cent of services in Chennai Beach - Tambaram - Chengalpattu operated. “Similarly, train services were restored in Chennai - Gummudipoondi section. The entire train operation will be put on track in another 24 hours,” the official said.

Track circuit-based signalling system

The track circuit-based signalling system, is an automatic one provided in Chennai Beach - Chengalpattu section. As soon as a train crosses, the respective green signal will turn red. Within a few minutes after the train reaches a safe distance, the signal will turn amber and further become green. The entire signal operation in suburban section is done automatically. Southern railway operates about 220 train services between Tambaram and Chennai Beach and 80 services run upto Chengalpattu