An unidentified man was killed yesterday morning when he was struck by a southbound Chessie System passenger train hurtling along at 70 mph in Beltsville. He was the second railroad fatality in Prince George's County in two days.

Police said the train operator slammed on the brakes and sounded the horn, but the man, who was walking on the tracks, did not move out of the way.

The accident occurred about 8:30 a.m. on the tracks that parallel Rte. 1 near Odell Road. It followed the death Wednesday of Elise Andrea Jorgensen, 77, who was struck by an Amtrak train as she crossed the tracks along Lanham-Severn Road in Seabrook, in an apparent attempt to keep her 7-year-old grandson from being hit by the train.

The deaths have fueled concern among state railroad officials, who said that Prince George's County has one of the state's worst records of railroad accidents and fatalities. Last year, seven of the eight railroad fatalities of pedestrians in Maryland were in the county. The accidents this week bring the number of pedestrians killed by trains in Maryland to four this year.

Prince George's County also has a disproportionate number of accidents at grade crossings -- areas where automobiles or pedestrians cross the tracks at the same level as the trains.

The county has 5 percent of the state's grade crossings but about 14 percent of the state's accidents have occurred there since 1975, according to Robert Herstein, coordinator of a federal railway improvement program for the Maryland Department of Transportation. Three of the five fatalities in car-train crashes at grade crossings last year were in Prince George's County, he said.

State officials also have identified a Prince George's crossing at Contee Road just south of Laurel as the worst in the state. Ten accidents have been reported there since 1980, Herstein said.

Other hazardous crossings in the county include Rte. 214 in Bowie, which is the third worst in the state; Sunnyside Avenue, which ranks 10th worst, and Cedarville Road, which is 12th worst in the state.

Hilmer Christianson, assistant commissioner of railroad safety and health for the state, said that an average of seven pedestrians die on Maryland tracks each year and that the state has the highest number of high-speed passenger train miles.

Railroad officials also point out that about half of the railroad pedestrian deaths are suicides, and most do not occur at legal pedestrian crossings. In the accidents, however, people usually misjudge the train, officials said.

"The most serious problem is that people miscalculate the speed of trains. A train traveling 120 mph travels one-half a mile in 15 seconds," said Clifford Black, an Amtrak spokesman.

Amtrak passenger trains travel up to 120 mph, while Chessie System commuter trains travel about 70 mph and freight trains run at 25 to 50 mph, officials said.

"People don't have a concept of how fast a train is moving. The time between when a train becomes a spot in the distance to something that's about to hit you is really instantaneous," Herstein said.

Officials advise pedestrians to cross train tracks only at legal crossings -- where there are signs, lights or bells to warn of an oncoming train. Crossing anywhere other than at a marked crossing is trespassing, Herstein said.

He advised pedestrians to stay clear of tracks when a train is passing.

"The suction on the side of the wheels from a fast-moving train can suck you under," he said. He added that ladders or other parts on the outside of the train could hit a person standing too close to the tracks and cause injury or death.

"Unless you see the train, most of the time you don't know it's there. And by the time you see it, it may be too late," he said.