The incident happened around noon at Idlewild Park and SoakZone in Ligonier, about an hour southeast of Pittsburgh.
TribLIVE reported that the boy is from Jeannette, and he hit his head when he fell about 10 feet as the car rounded a turn. TribLIVE also reported that the boy was in critical condition after having surgery.
Jeff Croushore, a spokesman for the amusement park, said the boy was conscious and talking when he was flown to Children's Hospital in Pittsburgh, about 50 miles west.
“(The investigation) is ongoing. I can't confirm everything. I don’t have the exact location on the ride (where he fell), but middle part of the ride, track,” Croushore said.
The ride, which passed inspection Saturday was closed indefinitely pending an investigation, according to WPXI, but Croushore said he couldn't say whether the ride malfunctioned.
The Rollo Coaster is a wooden roller coaster that opened in 1938. It was built by the Philadelphia Toboggan Company. Riders must to be at least 3 feet tall to get on Rollo, and anyone shorter than 48 inches has to ride with an adult.
Idlewild is the longest operating amusement park in the commonwealth. It was founded in 1878.
The incident comes just days after a 10-year-old boy was killed on a waterslide at Schlitterbahn Waterpark in Kansas City, Kansas.
Caleb Schwab, a Kansas lawmaker's son, suffered a fatal neck injury on the slide, which features a 17-story drop.