Picture, Park manager Debbie Halverson walks across the bridge at Lake Accotink Park where two people have been killed in the last two years. A photograph in last week's Virginia Weekly showing a bridge spanning Accotink Creek was not the bridge to which the accompanying article referred. By VANESSA BARNES HILLIAN--The Washington Post

Southern Railway and the Fairfax County Park Authority have been trying for almost a decade to keep youngsters away from the railroad tracks and train bridge at Lake Accotink, where two people have been killed in the last two years and dozens of youths have had near misses with trains.

A pedestrian bridge or tunnel may be the only solution, both railroad and park officials said last week, shortly after a 16-year-old county youth, Peter K. Dickinson, was struck and killed on the trestle by an Amtrak passenger train as he and a friend were taking photographs of the lake. The friend leaped off the trestle to the embankment, county police reported.

Last fall, an 18-year-old county youth was killed on the trestle by an Amtrak train. County police said later his death was a suicide.

Thousands of children regularly cross the tracks and trestle to get to the park, even though every year hundreds are arrested or given warning citations by railroad and county police for trespassing, according to Southern vice president James O. Greenwood.

The railroad spent $23,000 about six years ago for a chain link fence along the edge of the 400-acre park, Greenwood said, to separate it from several housing subdivisions and a newly acquired vacant 12-acre school site due to become part of Accotink Park in the next few years.

The fence, daily police patrols along the tracks and publicity about the danger--the outcome of meetings between the railroad and park authority--caused a temporary decline in track crossings, Greenwood said. But children on the tracks are again common and there have been many "near misses and many cases of rock and bottle throwing at trains" at Lake Accotink, he said.

Park authority director Joseph Downs said his staff has maintained the fence but cannot control the comings and goings of neighborhood children, who walk around the fence.

Downs said additional fencing and perhaps a network of paths leading under the trestle would help solve the problem, "but while we have $50,000 set aside to develop the old Carrleigh School site, money in the last park bond referendum, it probably would take more than that, and the bond money is not slated to be used until 1987 or 1988."

Greenwood said "an overhead walkway or something" may be necessary but that would be expensive. "But how expensive is a teen-ager?" he asked. Greenwood and park officials said they hope to get together within the next week or two to look again at the train safety issue.

The park authority is about to launch a $4.2 million cleanup of the badly silted lake, also funded in last fall's park bond referendum.

A photograph in yesterday's Virginia Weekly showing a railroad bridge spanning Accotink Creek was not the bridge to which an accompanying article referred. The bridge where two people have been killed in the last two years crosses the creek farther north, near Lake Accotink in Springfield.