This social media user captured the fire...
Ahh, New York ❤️🔥 pic.twitter.com/d6kG7A7AIf— Stephen (@Stibbanski) January 21, 2018
The incident snarled subway traffic for an hour, as the F trains were rerouted first to the A line, then over to the E line. Service resumed within an hour.
Per ABC 7: "Authorities have not confirmed how the fire started or who caused it."