KARACHI, March 22: The biggest port city of the country that remained cut off through railways from the rest of the country owing to the Thursday evening bomb blasts on tracks was reconnected in around four and a half hours and the normal traffic resumed in the early hours of Friday, officials said.Responding to Dawn queries, a railway official said the railway traffic remained suspended from 8.30pm on Thursday to 1am on Friday, when a railway track was damaged near the Bin Qasim station. He said nine trains — seven of them up and two down — were delayed.