Two men were beaten and robbed while riding the escalators out of two different Metro rail stations late Friday night, transit police reported yesterday.

The similar incidents, which police believe are the first of their kind on the 2 1/2-year-old transit system, occurred 90 minutes apart -- first at the Foggy Bottom station, 23rd and I streets NW, and then at Deanwood, 48th and Polk streets NE.

In both cases the victims were men traveling alone at a time when the subway is lightly used. Both men said they were attacked by two welldressed males, one wearing a stocking cap, apparently in their 20s.

Police said the victim in the first incident, Mark Eisen, 24, of Springfield, was struck on the forehead with a hard object and robbed of about $50, while riding the escalator at Foggy Bottom at about 9:45 p.m.

Afterward, he was led across the street by two passersby to George Washington University Hospital, police said, and received 20 stitches to close two lacerations on his head.

Police said the victim in the second incident, Bernard Livingston, 42, of Southwest Washington, was punched in the mouth while leaving the Deanwood station at 11:10 p.m. He lost several teeth, police said, and seven one-dollar bills were taken from his pocket.

Dennie W. Stewart, assistant chief of the transit police, said there have been no other robberies involving force on the subway system since it opened and only a small number of purse-snatchings and pickpocket incidents.

In an interview, Eisen said his assailants were passengers on a bus that he boarded in Springfield. Then they boarded a Metro train with him at National Airport, he said, and left the train when he did at Foggy Bottom.

Eisen said he was first accosted by the men, one of whom said he had a gun, while on the mezzanine of the Foggy Bottom station, but Eisen said he broke away and ran back to the platform. He said he was unable to find a station attendant or policeman to report the incident, but thought it was safe to leave the station after waiting about 10 minutes.

While riding up the escalator, Eisen said he noticed one of the assilants standing at the top and the other one following him below. Eisen said he decided to try to run down the escalator, but was struck on the head while he did so, knocked down, and robbed.

The escalator carried him up to the street level, Eisen said, where he stood up and staggered around until the passersby led him to the hospital.

The Foggy Bottom and Deanwood stations are about seven miles apart at opposite ends of the city. Travel time between them is about 24 minutes, officials said. Foggy Bottom is on the Blue Line, and Deanwood is on the Orange Line, but the same trains currently serve both stations.