A tractor trailer accident provided scary moments outside Grand Central Terminal Tuesday afternoon.

Witnesses said a tractor trailer collided with a concrete railing on the elevated Park Avenue roadway around 4:15 p.m. Tuesday.

Fire officials said debris fell from the upper roadway onto the street below.

Witnesses described a chaotic scene.

"We were walking down the street, everything was normal and we heard a strange, crashing, popping above us, saw concrete starting to slowly fall," said one.

"We heard the truck strike the abutment on the Pershing Square Bridge," said another. "We then saw the awning collapse on a huge cloud of dust."

There are no reports of any injuries.