Metro services were disrupted for nearly six hours from afternoon till the end of the day's operations on Tuesday after an air-conditioned rake got stuck at Netaji (Kudghat) station.

Snags often tripped Metro before the service was suspended in March because of Covid-19. The service resumed two weeks ago.

On Tuesday, the Dum Dum-bound train was at Kudghat station around 2pm when the snag occurred, said a Metro official.

The train had to be vacated as the snag could not be fixed immediately. But little did officials anticipate that the train would remain stuck beyond the end of the day’s operations, after which it was taken to the Noapara car shed.

Initially, Metro ran a truncated service between Noapara and Maidan, where there is a provision for trains to take a U-turn. Later, the truncated service was extended till Tollygunge. Trains did not run between Tollygunge and New Garia for the rest of the day.

The snag was traced to a third rail current collector — an equipment attached to the undercarriage of the train that collects power from the third rail of a Metro track. Each compartment in a rake typically has four such current collectors on either side.

“The pad of a current collector was damaged. It was dragged for around 300m and further damaged the other three collectors of the rake on the same side. The power supply from the third rail was disrupted,” said a Metro official.

Before the pandemic, Metro used to run 288 trains every weekday and the average daily passenger load was well above 600,000. Back then, most glitches were attributed to an ageing and overstretched fleet.

But since the service resumed on September 14, Metro had been running 110 trains every day. It was increased to 116 on Monday. The average passenger count started from 20,000 and is yet to reach one-tenth of what it was.

“Today’s glitch cannot be linked to the number of trips made by the train. There is a possibility that the current collector came in contact with a foreign object,” said the Metro official.

The train that got stranded on Tuesday is one of the ne-wer lots built at the Integral Coach Factory in Perambore, Chennai.

“There were some issues with the new rakes. But when the services were suspended (because of Covid), most issues were addressed. Tuesday’s problem is a new one. We will conduct a detailed examination to ascertain the cause,” Metro general manager Manoj Joshi said.