Central Station was thrown into chaos on Saturday night as fire engulfed the Hungry Jack restaurant in the main concourse of Sydney's main railway station.
Black smoke billowed out from the fast food chain as alarms throughout the station went off at 6pm.
"You couldn't see anything it was just black smoke covering the whole street," said Bradley Faragher.
Commuters were evacuated from both the central concourse area and from platforms one to 15.
"It was really scary," said 16-year-old Courtney Waugh. "Especially when all the alarms started going off at once and we had to rush out.
Courtney was on her way home to Dubbo with her mother Wendy Gilchrist after a marathon day of travelling down from Queensland.
"We are stranded," she said.
It is believed the blaze broke out in or near the Hungry Jacks on the station's main concourse.
About 1000 people were evacuated after the fire spread across four levels via ducting, Fire & Rescue NSW tweeted.
Firefighters now have the fire under control, although platforms one to 15, which run intercity trains, are still closed.
Nearby streets have been blocked off due to the fire.
At least 10 fire crews are at the scene, with firefighters using breathing masks to enter the usually busy station in an effort to find the cause of the fire. There are no reports of injuries.
All trains have been stopped around the station and serious delays are expected.
"Passengers are advised to allow additional travel time, listen to announcements and check indicator boards," a Transport Management Centre spokeswoman said.