Why I work from home.

The operator of a Chicago commuter train that crashed at O’Hare International Airport acknowledged she dozed off before the accident and had also done so last month when she overshot a station platform, a federal investigator said Wednesday.

Before the crash, the operator had been running trains on the nation’s second-largest public transportation system for just two months. In Monday’s accident, which injured more than 30 people, she woke up only as the eight-car train jolted onto the platform and barreled up an escalator leading into the airport. The accident occurred around 3 a.m., as the driver was nearing the end of her shift. The woman had an erratic work schedule and investigators were looking to see if that played a role in her evident fatigue.

“She did admit that she dozed off prior to entering the station. She did not awake again until the train hit,” National Transportation Safety Board investigator Ted Turpin said at a final on-site briefing at the airport.

She’s been on the job for only two months and this is the second time it’s happened. Her supposedly “erratic work schedule” hadn’t even had time to take a toll yet.

Her labor union weighed in with its defense:

The union representing the operator has said she was working a lot of overtime recently and was exhausted. The CTA said she had more than the eight-hour off-duty time required before starting her shift.

Gosh, she was tired. Had her job already worn her out during her first month when this last happened?

Maybe someone who has a hard time staying awake at work shouldn’t have a job that puts the lives of others in her hands. She sounds more suited to a DMV gig.