The fire was reported around 4:18 a.m. Friday at E Street and Kensington Avenue.
Firefighters first saw smoke, then flames began reaching for the sky as crews were forced to attack from the outside.
The location is along SEPTA's Market-Frankford Line. SEPTA said it is monitoring the situation but, so far, there are no impacts to service.
No injuries have been reported. It's not yet known how the fire started.
The city's Office of Emergency Management says residents in the area should keep their windows closed due to the smoke conditions.