Utah Transit Authority officials suspect a mechanical failure caused an unoccupied light rail car to decouple from a TRAX train, leading to a collision that injured three people.
The wreckage remained on the track overnight and well into Wednesday morning as UTA crews worked to remove the car and the train that struck it, as well as complete inspection of the rails for any damage. Blue Line and Red Line trains experienced 15-minute delays as the commute began.
By 9 a.m. Wednesday, UTA spokesman Remi Barron said, the damaged cars had been removed and full service through the accident scene near 8100 S. State Street restored. By afternoon, all trains were back on schedule.
Prior to clearance of the wreckage, UTA was diverting trains onto the opposite track to maintain service, albeit at a slower pace.
The empty decoupled car, a rear unit of a northbound Blue Line train, came loose about 8:30 p.m. Tuesday. About 15 minutes later, the next northbound train on that line did not have time to stop, though the operator applied the brakes before slamming into the car at an estimated 40 mph.
The operator and two of the six passengers onboard were treated for minor injuries. The operator was treated at the scene and the two passengers were taken to the hospital, Barron said.
The specific reason the car uncoupled — and why it went unnoticed until the crash — remained under investigation Wednesday afternoon. How long it would take to determine the circumstances of the incident was unknown.
Barron did say there was no memory of a similar car-decoupling incident in the history of the light-rail system in Utah.