Emergency personnel were using ladders to retrieve people stranded on a monorail at the Dallas Zoo.
Monorail Safari stopped today after an off-zoo power surge. Our amazing guests stayed calm & cheery as Dallas Fire helped them down.
— The Dallas Zoo (@DallasZoo) August 6, 2014
In recent years it's malfunctioned on at least two other occasions, each time requiring emergency workers using ladders to rescue passengers.