A smoke condition disrupted subway service Saturday afternoon on the F line between Manhattan and Brooklyn, the MTA said.
The service was restored by about 6 p.m.
Firefighters were investigating whether the smoke near the Broadway-Lafayette station was due to a track fire, the MTA said.
For about an hour and a half, there was no F train service in either direction between Manhattan and Brooklyn.
The F trains were being rerouted to the E line, which caused delays there, the MTA said.
There was also no E train service south of 34th Street-Herald Square, the MTA said.