The B&O railroad's usually uneventful commuter runs between Washington and Baltimore have become increasingly unnerving experiences in the past week as vandals have placed such obstacles as washing machines, tree trunks and auto tires in the way of the trains.

At least five times since last Thursday, the vandals, who have generally operated in an area slightly south of Laurel, have piled debris on the tracks, delaying commuters and creating the danger of derailment.

Railroad officials said yesterday that the vandals have also pelted the train with rocks on several occasions.

"In the last several days, it's been a phenomenon morning and night," said Paul Willis, a regular passenger. "Either the train is forced to stop or there is a terrible dragging sound as something catches underneath, he said, adding that he and other passengers have become concerned about their safety.

Earlier this year, debris piled on the B&O tracks derailed one passenger car in the same area, near Contee Road, where the current episodes of vandalism are occuring, according to John H. Griffin, manager of passenger operations for the Chessie system, which includes the B&O railroad.

No one was hurt in that incident, Griffin said.

Griffin added that recently the vandals have become more persistent. On Monday a large obstacle was placed on the tracks in the afternoon and knocked out of the way by the 5:05 p.m. train from Washington. Vandals then replaced the same object in time to have it hit by the next northbound train, damaging the underside of one of the two cars and disabling its engine.

Far from uncommon, the type of vandalism occuring in northern Prince George's County mirrors a nationwide epidemic of vandalism against railroads that has cost the railroads millions of dollars and endangered hundred of lives.

"It's a countrywide sickness," Griffin said. "Everybody likes to throw things at trains, pile stuff on tracks and throw things from bridges." He said that trains have been outfitted with plastic windows and metal grates to protect windshields from such hazards as cinderblocks dangling from overhead bridges.

The obstacle placed on the B&O tracks Monday night was a truck tire weighted with rocks. When the train collided with it, "It made a hell of a lot of noise and woke up a lot of people who were sleeping," said Gus Nunez, a commuter who lives near Catonsville

Kay Cassady, another commuter on the northbound 5:05 train last night said, "I wasn't really concerned until I started talking to several people, and they said that the train could be derailed -- that frightened me a lot."

A railroad policeman was riding on last night's train and two others were patrolling the area where the problems have occurred, according to railroad employes.

"They try to blame it on the kids, but some of this stuff is pretty durned heavy for kids," said trainman Dan Solloway. Solloway said that the debris was usually placed on a curve in the railroad tracks where it could not be seen ahead of time.

Solloway and conductor R.C. Burns said they had both been alarmed by the incidents. "It's dangerous. Everytime you hit something, you don't know if you're going to derail or not," said Burns.

During last night's commuter run there were no incidents of the type that have plagued the train for the past week. The train was forced to slow down as it approached the Capital Beltway, however, because signal lights along the track had been shot out, according to the conductor.

"Vandalism is an awful problem for the railroads," said Burns.