A Chicago train operator, whose train derailed last month when she dozed off, has been sacked, officials say.
Thirty-two people were hurt when the Chicago Transit Authority train jumped its tracks at O'Hare International Airport and hurtled up an escalator.
The woman, 25, worked as an operator for two months and reportedly admitted it was not the first time she had dozed off at work.
None of the injuries at the busy airport was said to be serious.
The Chicago Transport Authority (CTA) said that it did not believe the driver's work schedule played a role in the 24 March crash.
But it said that changes to its train operator scheduling policies would be implemented as result of an internal review of the crash at O'Hare.
CTA officials were quoted in the Chicago Tribune as saying that the driver had worked 55 hours in the seven days preceding the incident but was off work for 18 hours prior to the shift in question. Officials say that she also admitted to over-running a station in February.
CTA spokeswoman Tammy Chase was quoted by the Reuters news agency as saying that it could terminate the contract of an operator for two serious safety violations and that "an incident of this severity is sufficient for termination".
The National Transportation Safety Board (NTSB) said that train was travelling at about 42 km/h (26 mph) when it entered the station, a normal speed, and tripped an emergency braking system beside the track that failed to stop it before the impact.
NTSB investigator Ted Turpin said last month that the train operator had admitted that she had "dozed off" prior to entering the station.