The National Transportation Safety Board released an initial report from the investigation of the train that derailed at Chicago's O'Hare International Airport last month.
The preliminary findings showed there was too short of a distance between the end of the train track for the emergency braking mechanism to deploy properly.
According to the NTSB's analysis, the Blue Line train was advancing at 26 mph when it passed a "trip stop" that activated the emergency brakes, the Wall Street Journal reported. But the train was running far too quickly to allow the brakes to activate correctly after hitting the signal.
32 people were hurt in the March 24 accident, but none of the injuries were serious. No deaths were reported.
The train operator admitted to falling asleep behind the controls when the train crashed into a bank of escalators.
Chicago Transit Authority officials told the Chicago Tribune on Friday that the driver had been fired.
The train operator, who worked on the rails for just two months, reportedly fell asleep while running the Blue Line at about 2:50 a.m. The train veered off the rails and hit the escalators leading to the airport's terminals two minutes later.
The CTA employee reportedly awoke with a start to see the lead car crash into stairs and escalators by the end of the track.
This wasn't the first time the train conductor had fallen asleep at the controls. She also admitted to overshooting a station in the past.
National Transportation and Safety Board investigator Ted Turpin acknowledged that the woman was "very forthcoming" in her acknowledgment of responsibility for the incident during initial questioning.
"She dozed off prior to entering the station," Turpin told CNN. "She did not awake again until the train hit close to the end of the bumper."
Turpin told CNN two days after the crash that certain backup systems should have come to the train's aid, but did not.
Video footage captured the derailment - the YouTube spot shows the train entering the Chicago airport's station, then slamming into the escalators.
