Service has resumed on the 4, 5 and 6 lines following FDNY activity at the 14th Street-Union Square station, the MTA said.

An FDNY spokesman said a small track fire broke out around 5:12 p.m. Thursday. The fire was under control and service resumed about an hour later, MTA and fire officials said.

Customers can expect some residual delays on the 4, 5 and 6 lines.