Rescue workers used inflatable air bags to free a man whose leg got caught between a Metro station platform and a train last night at the Crystal City stop, officials said. The man's legs were described as severely hurt, but the injuries were not believed to be life-threatening.

It took about 15 rescue workers from the Arlington County Fire Department 10 minutes to extricate the man by placing two Kevlar air bags between the train and platform and pumping them with air, pushing the train forward several inches, Battalion Chief Robert Cornwell said.

The 23-year-old man, whose identity was not immediately available, was "obviously in shock," said Sgt. Erhart Olson, of the Metro Transit Police. The man was flown by helicopter to Washington Hospital Center, where he was listed in serious condition early today.

Investigators were trying to determine late last night how the man's left leg, from the foot to the knee, got caught between the platform and train. It was not clear whether the train was moving at the time.

"We have no idea how he got wedged in there," Olson said.

The incident occurred about 10:15 p.m., as the train, which was out of service, pulled into the Crystal City station on the Yellow and Blue lines, transit police said.

Both sides of the track at the station were out of service for about 10 minutes, officials said, and two-way traffic was then switched to a single track. Full service was restored in both directions shortly before midnight.

CAPTION: Rescue workers rush a man to the hospital after one of his legs was pinned between a Metro train and the platform at the Crystal City station.