According to the latest news reports, the cleaner did not try to steal the train, but started it accidentally whilst cleaning it. The rail company is now being investigated.
From the BBC news.
"A cleaning lady accused of commandeering an empty Swedish commuter train which crashed into a house did not steal the vehicle, officials say.
Prosecutors in the capital, Stockholm, said that they had closed the criminal case against the woman, who sustained serious injuries in the accident.
They said they now believe she started the vehicle by accident as she was cleaning it in the middle of the night.
The woman had initially been accused of stealing the train.
On Friday, the prosecutor said the cleaner was no longer suspected of wrongdoing.
"Everything suggests it was a pure accident where several temporary and unfortunate circumstances caused the woman to set the train in motion when she was cleaning," Paer Andersson said in a statement, according to AFP news agency.
No-one was hurt in the building which was hit when the train came off its tracks in the early hours of Tuesday in the suburb of Saltsjoebaden.
The train operating companies, Arriva and SL, may now face an investigation into a possible breach of safety laws.
A spokesman for Arriva said it was unfortunate that the woman, who was detained in hospital on suspicion of destroying public property, had been described as a thief."