Swedish authorities have dropped a criminal investigation against a woman previously suspected of stealing a commuter train that crashed into an apartment building.

Investigators on Friday said the woman probably started the train by accident as she was cleaning it at a depot early Tuesday.

The four-car train rolled about a mile (1.6 kilometers) to the end station of the railway line, where it jumped off the tracks, careered for about 30 yards (25 meters) and crashed into a three-story building.

No one was hurt except the woman, who was airlifted to a hospital with serious, but not life-threatening injuries.

Prosecutor Par Andersson said she appears to have put the train in motion through a series of "unfortunate circumstances," but is no longer suspected of a crime.