(CBS) – The operator who dozed off and ran her CTA Blue Line train through a bumper and up an escalator one year ago this week at an O’Hare Airport terminal describes the circumstances that preceded the accident, in newly released federal records.

Brittney Haywood’s 80-page interview — done the day after the March 24, 2014, accident — reveals a woman who said she liked to work overtime but knew even before the accident that staying awake was a “challenge” between 2 a.m. and 3 a.m., the time of day when the accident occurred.

“I was tired,” she said in her first comments to the investigating team from the National Transportation Safety Board. “I didn’t get any sleep the day before, and I might — I have — I became sleepy and I nodded off into the terminal of O’Hare.”

Haywood has not spoken publicly about the accident, which injured 30 and caused approximately $9 million in damage.

She said she had worked 55.7 hours in the week before the accident, some of it as a flagman but most of it as a train operator. She had just marked her two-month anniversary as an operator.

While she said she was able to get a full day’s sleep before coming to work that Sunday night, she said she had sacrificed most of her off-time the day before for a flag football practice. She estimated that she napped afterward for 50 minutes, but said even that small amount of rest made her half an hour late for work.

She was due at 4:55 p.m. but arrived at 5:22 p.m., she said. Haywood said she would be given a “miss” for reporting late. She had received another “miss” the month before when she dozed off momentarily and overshot the station platform at Belmont. She said she was aware that four “misses” in a year meant termination.

The trip on which the accident occurred was the fourth between the O’Hare Blue Line terminal and Logan Square. Five round-trips were on her schedule. She said she reported with a cold that she had been nursing for the past week, but was not on medication, just green tea. She said she began to feel tired at the Harlem station and turned off the heat to try to stay alert.

Haywood said she remembered stopping at Rosemont and seeing signals just outside the portal of the tunnel leading to the O’Hare terminal. She said she remembered nothing after that until hitting the trackside “trip” that automatically sets the emergency brakes at the end of track. She said she was trying to move the controller handle from power to emergency braking but “was too late.”

Asked for her opinion about the CTA and safety, Haywood told investigators the transit agency’s main goal was to “keep the trains moving.”

She was quick to add: Better “safe than sorry.”

CTA fired Haywood 10 days after the accident. It almost immediately lowered the speed limit on its O’Hare platforms to 15 mph from 25 mph, moved the trip arm farther from the bumper post and re-emphasized its fatigue-awareness training program for rail operators.