Steven Throop, 13, was in Washington for the July 4 holiday, staying with another family in a mobile home in Southwest. Tuesday night, about an hour before the fireworks were scheduled to start. Throope and a buddy walked the 50 feet from the mobile home to the unfenced railroad yard at Seventh and D street SW and climbed on top of a parked Baltimore and Ohio railroad car.

Throop is now listed in critical condition at Washington Hospital Center's burn unit suffering from burns he apparently sustained when he touched the 11,000-volt wire that runs just a few feet above the box car.

The incident is similar to one that occurred on June 22 in another Conrail freight yard on Benning Road at Kenilworth Avenue NE. In that incident, two youngsters climbed on top of a parked box car and suffered severe burns when they came to close to the electrical wire above.

The track at Seventh and D Street - a single track where box cars are occasionally parked - was the place where, in 1971, 41-year-old Preston Morris of Northwest Washington was killed and police Sgt. Raymond Zilko was injured trying to rescue him.

Following that incident, the National Transportation Safety Board issued a report criticizing Penn Central - which then owned the track - for not fencing in the area and for posting stencilled warning signs that were "inconspicuous and marginally legible."

The wires in question are 11,000 volt power lines that supply the electricity to power the trains. The lines radiate an arc of power that will shock any ungrounded object within three feet.

Conrall spokesman Tom Hoppin in Philadelphia said yesterday that "generally speaking, we have found that fencing is just not a viable alternative.

"The best way to deal with these things is through the educational process." Hoppin said, explaining how a program instituted in Philadelphia to teach railroad safety to children reduced the number of incidents.

"The educational programs are much more effective than a fence, which many persons just interpret as a challenge," Hoppin said.

One Conrail employe here - who said he was under instructions not to discuss the incident publicly - said, "I've heard a lot of talk about fencing, but it's mostly just scuttlebutt, unless the government wants to subsidize it. They (Conrail) are already a broke railroad."

"If there was a sign out there, it would have probably disappeared, especially on the Fourth of July. Signs have a habit of disappearing," he said.

That particular area of track is used by people "as a sidewalk," he said. "They're already cutting holes in the Metro fence."