A young child was shaken up in the accident.
The investigation into how this happened is underway.
The small rollercoaster started to come off of the tracks at the waterfront park in Dobbs Ferry at around 4 p.m.
Adults ran to hold the Orient Express kiddie coaster up where it had derailed to prevent the children onboard from getting hurt.
"We we're definitely holding it up," said Jeremy Schumacher, a good Samaritan. "I was definitely using muscle to keep it upright."
Onboard at the time was a 5-year-old girl in the front and a mother with a younger child in the back.
Those in attendance say they didn't hear any loud noises but noticed when the coaster came to a sudden, abrupt stop.
"We were here last year and it was great," added Dobbs Ferry's Lauren Mathieson. "It really makes me cautious.
The rides were taken out of commission, but the concessions at the carnival remained open. The rides were inspected by the state labor commission on July 3, when the carnival was set up. They will have to be reinspected before running again.
The carnival rides are by Shamrock Rides and Amusements based out of Milton, NY.
So far, there is no comment from ownership.
The 5-year-old girl was assessed and stabilized at the scene and released with no injuries.
The carnival will continue to partially operate through Sunday.
ALSO READ | Exclusive look into NYPD's new technology, safety precautions for 4th of July celebrations
Exclusive: NYPD's new safety technology, preparedness for 4th of July
----------
* More Northern Suburbs news
* Send us a news tip
* Download the abc7NY app for breaking news alerts
* Follow us on YouTube