The woman was walking near the tracks on Main and Dallas around 6:40pm when she was hit by the train and trapped below it.
Downtown was full of cars and people at the time. The train had a number of passengers on board. It was going about 20 miles per hour when it collided with the woman.
The female pedestrian was rushed to the hospital after being trapped for almost half an hour. She was conscious and talking. The initial impact indicated much worse.
"It started and it stop, stop, stop like something was actually underneath the train," passenger Adam Dupre said.
Passengers felt the impact.
Mike McKenzie saw it from the back of his taco truck.
"Right when I heard the first thud, I turned and saw it, I guess, her go underneath," McKenzie said.
According to METRO, the woman was walking on the tracks near Polk toward the train. The driver sounded the horn, but she never moved. She was struck and pulled under. The train came to an abrupt stop.
"Everybody was just shocked, they were taken aback. Everybody was on their phones, everybody was trying to see what had happened. We couldn't get a good angle but all the police and the ambulance showed up and it was chaos," Dupre said.
The woman ended up under the cab and not the wheels. And on this scene Houston firefighters didn't use hoses, but rather airbags for the rescue.
"To help lift the train just a couple of inches, she wasn't that far under there. It required a couple of inches of life to get her up from under the train," METRO Spokesman Jerome Gray said.
Once out, she was on her way, alive but with critical injuries. We're told she is in critical but stable condition and has pelvic and spinal injuries.
Service from downtown Houston to the University of Houston was shut down for about an hour and half as emergency responders tended to the woman and cleared the scene.
METRO officials are now looking at video to see if the woman was aware that the train was approaching.