Train services on the BarrackporeNaihati section of Eastern Railway's Sealdah Division were disrupted for three hours on Friday, due to a signal failure, an ER official said.
Six pairs of EMU locals were cancelled and 40 trains ran behind schedule, owing to the snag, inconveniencing thousands of passengers during the busy morning hours.
"A signal failure from 7.24 am in all the four lines at Shyamnagar station caused the disruption," an ER spokesman said.
Five express trains were also detained en route, he said.
Normal services were restored at 10.17 am following necessary repair work.