Investigators believe the smoke was caused by a moving train striking an object on the tracks, officials said.

Service on the 1 subway train was restored late Tuesday afternoon after a southbound train hit some debris on the track and caused a smoke condition in the 191 St. station in Manhattan. Fire

The No. 1 subway line was suspended in both directions between Manhattan and the Bronx on Tuesday, according to the MTA. There was no service between the 215th Street station in the Bronx and the 145th Street station in Manhattan.