Updated

About 100 people were rescued Saturday by firefighters after a monorail at the Dallas Zoo stopped operating because of an unspecified malfunction.

Dallas Fire Rescue spokesman Jason Evans said no one was injured as a result of the incident.

Local television stations reported that the train was between 15 and 20 feet off the ground when it stopped. That height is among the lowest the train reaches during the 20-minute tour.

Firefighters responded to a 911 call about 3:30 p.m. after the train stopped moving. Evans said an unspecified malfunction occurred. He said as many as five extension ladders at a time were used to remove the passengers.

He said the rescue, which took about 30 minutes, was made easier because firefighters had easy access to the passengers.

The zoo's website says the monorail is the only one in the U.S. that can "climb and turn, taking guests on a one-mile tour through bush, desert, forest, woodland, river and mountain environments."