A Fair Lawn firefighter was injured battling a large brush fire Saturday afternoon behind the railroad line on Main Street in Glen Rock.

Glen Rock Fire Chief Thomas Jennings said from the scene that the cause of the fire is unknown, though it spread quickly on a fairly hot, dry spring day.

The name of the firefighter was not released. He was taken to Valley Hospital with shortness of breath and was in stable condition, authorities said.

Jennings estimated the fire, which started just before 1:30 p.m., extended about 400 feet from the west side of the train line into the woods, burning through what appeared to be the length of several football fields.

No buildings were damaged. New Jersey Transit trains on the Main Line were halted for several hours as firefighters fought the fire from on the train tracks.

“It spread really quickly," Jennings said at about 2:15 p.m. "We've got a ways to go. We'll probably be here for another two hours."

Flames could be seen from nearby houses on Main Street, though within an hour most of the flames had been doused. Fair Lawn and Hawthorne assisted Glen Rock.

The fire was killed at around 3:30 p.m. and the closed Main Line re-opened shortly thereafter.