and up an escalator at o'hare airport. ntsb investigators say the operator of the train admits she fell asleep at the controls. >> she did not wake again until the train hit the end of the bumper. >> reporter: take a closer look. you can see the train approaching in the distance. standing nearby, a commuter and an officer chatting. in a panic, they run for safety. 32 people on board the train suffer minor injuries. >> it felt like somebody punched me or something. then the lights went out. >> reporter: at the same time, the same train operator was reprimanded back in february, where she, quote, shut her eyes for a moment, and the train had overshot the next stop. >> the driver often working overnight swing shifts. the automatic brake system was activated but failed to stop the train. alex perez, abc news, chicago. >> just unbelievable video. >> we work the overnight shift. we know how difficult it is. but we're not driving trains. >> we're not driving trains, exactly.