CONCORD, N.H. – A teen-age girl struck by Amtrak’s Downeaster train escaped with cuts and bruises, but the accident should serve as a warning about the dangers of the high-speed railway, police and rail officials said Tuesday.

The passenger trains, which began running from Portland, Maine, to Boston last December, are much quieter than the old freight trains, said town Police Chief David Kurz.

“You can’t hear them until they’re by you” because of new, seamless rails, Kurz said.

David Fink, executive vice president of Guilford Rail Systems of Billerica, Mass., the track owner, said he hopes the accident will prompt state legislators to pass a bill that would increase the penalties for criminal trespassing on high-speed rail lines.

House Bill 1385 would require railroads to post no-trespassing signs and would fine violators $100 for a first offense, $500 for a second offense and $1,000 for a third. Maine and Connecticut have enacted similar laws, Fink said, but the New Hampshire bill is in a study committee.

“I think that this near-miss may have the legislative people taking another look at it,” he said.

Samantha Leclair, 17, of Seabrook was jumping off a trestle at a popular swimming spot Monday afternoon when a southbound train came around a bend about 600 yards away, going about 40 mph, police said.

The engineer sounded his whistle and quickly pressed the emergency braking button, releasing sand on the tracks that helped him gain traction to slow down.

Several of Leclair’s friends jumped from the bridge into the Lamprey River, but she was on a section of the trestle that was over rocks, so she apparently tried to outrun the train. The engineer believes he struck her as she jumped to the side, Kurz said.

“He felt or heard a thump as if he had hit a deer, and then saw her fly through the air,” Kurz said.

Leclair landed partway down the embankment. She was in fair condition Tuesday at Wentworth-Douglass Hospital in Dover.

“She’s one lucky kid. There’s no question about it,” Kurz said.

Six young people at the swimming hole were charged Monday with criminal trespassing, and Leclair also will be charged, Kurz said.

Yet three hours later, teen-age swimmers were jumping from the same trestle.

“There’s a little Huck Finn in everybody, and I’m sure generations have swum from that bridge,” Kurz said.

Police and railway officials try to patrol the area, but trespassers are difficult to catch, he said. Cruisers traveling on gravel roads make more noise than the trains and by the time police get there, the swimmers have scattered.

The Downeaster is authorized to operate at a top speed of 59 mph, but authorities said trains are ordered to slow down as they approach the trestle on hot days because of its popularity as a swimming spot.

Guilford Rail Systems also requires engineers to travel at 40 mph on that section of the line when temperatures are above 90 degrees because of the increased risk that the track will buckle, Fink said. The temperature was well into the 90s Monday.

John Law, safety director for track owner Guilford Rail, commended the engineer.

“If he had been going 60, we would have a fatality down there,” Law said.

The accident delayed the train by two hours and 12 minutes.