ATTLEBORO - A 45-year-old man was struck by a high-speed Acela Express train near the downtown train station Tuesday afternoon, seriously injuring his right arm.

The victim, identified as John Cullen, who has addresses in Attleboro and Norton, was driven to Sturdy Memorial Hospital by a passerby and was later transferred to Rhode Island Hospital in Providence, police said.

Cullen was listed in fair condition several hours after the accident.

Cullen was on the northbound train tracks when he was struck about 120 yards north of the station by a northbound Acela train traveling about 140 mph, authorities said.

After the accident, the train managed to stop several hundred feet near the Holden Street overpass. A witness, Mildred Little of Mansfield, said the man was bent over picking something up and looked up after the train blasted its horn.

"I saw the whole thing," said Little, who was at the train station waiting for an MBTA commuter train.

She said the man tried to avoid being hit by leaning against a chainlink fence that separates the northbound and southbound sides of the tracks, but that the train scraped his arm.

A man on the scene offered to take Cullen to the hospital, and another man gave him his shirt to bandage his arm, Little said.

Attleboro police were notified about 1:30 p.m. and train service was stopped for about a half-hour while investigators for Attleboro and Amtrak police examined the scene.

Police do not know the identity of the passerby who gave Cullen a ride to Sturdy Memorial Hospital, Detective Lt. John Otrando said.

Cullen has addresses listed at 15 North Main St. in Attleboro and 108 West Main St. in Norton, police said.

It is against the law to be on the tracks.

Cliff Cole, an Amtrak spokesman, said a "trespasser" was struck by an Acela Express train running from Washington, D.C., to Boston.

The posted speed limit is 150 mph, Cole said. There were 132 passengers on the train and no reported injuries to either passengers or crew. The train was delayed about 45 minutes on its arrival in Boston, Cole said.

The incident is under investigation by Amtrak police.