A homeless man who scavenged for copper wire was critically burned inside an Amtrak electrical substation Saturday night and hung from a high beam for two hours, groaning and flailing, while rescuers waited for Amtrak electricians to arrive.

Hospital officials identified the man as Wendell Edmondson, 36. Shelter records show he lived in the old Randall Elementary School shelter across South Capitol Street from the substation. He was listed in critical but stable condition yesterday in the burn unit of Washington Hospital Center.

The delay in rescuing Edmondson angered D.C. fire officials, who said they believed Amtrak officials did not grasp the seriousness of the situation quickly enough. Amtrak officials said they were following important safety procedures.

About 9:45 p.m. Saturday, someone at a McDonald's restaurant next to the substation noticed Edmondson inside the fence surrounding the 13,000-volt facility and called authorities. Other passersby said they saw a flash of electricity like lightning.

About 10 p.m., D.C. firefighters found Edmondson dangling from an overhead beam about 15 feet in the air, upside down and naked, his clothes apparently burned off. The fire department called Amtrak's operations center in Philadelphia to say there had been an accident and to shut off the power, Amtrak spokesman Bruce Heard said.

At 10:10 p.m., Amtrak officials called the Potomac Electric Power Co., according to Pepco spokesman Steve Arabia. Within five minutes, Arabia said, workers at Pepco's Benning Road facility had shut off the power that fed the substation.

Fire and rescue workers then were ready to enter the substation, but Amtrak officials advised them to wait because two other power lines also fed into the substation and might have been electrified. These high-voltage lines came from Amtrak's Landover station and from Union Station, Heard said.

Heard said Amtrak procedures call for electrical engineers to inspect the substation to make sure all the lines are off and the equipment properly grounded before anyone is allowed inside.

Capt. Ted Holmes, a fire department spokesman, said fire officials made at least three calls to Philadelphia in an attempt to get Amtrak personnel to the substation. He said officials there did not respond immediately.

The nearest team of electricians had to drive from their homes in the Baltimore area to their Odenton, Md., station for trucks and equipment, then to the accident site about 45 minutes away, Heard said.

Holmes said Fire Chief Ray Alfred plans to write Amtrak officials to determine what went wrong Saturday night, and to establish a more efficient procedure in case a similar incident occurs.

Heard said he is not aware of any Amtrak procedure for allowing other electricians to declare a substation safe in an emergency.

"We followed the proper procedure to a T," Heard said. "You don't know there is no power remaining until you check it. Even though everybody says the power is turned off, you don't know until you test it."

The Amtrak crew arrived at 11:20, which Heard said "is frankly a pretty good response on a Saturday night."

The crew determined by 11:40 that all power was shut off, and that no residual power was in the substation, Heard said. Edmondson was freed at 11:50 p.m. by two Pepco workers and a fire rescuer in a Pepco bucket truck. He was flown by MedStar helicopter to the Washington Hospital Center.

The substation, next to Conrail freight tracks, lowers the voltage of electric current that operates Amtrak switches and signals. Because of the accident, Heard said, one train traveling from Atlantic City to Richmond was delayed 12 minutes.

Shelter residents said Edmondson wandered the streets and concrete wasteland under the Southeast Freeway, pushing a shopping cart and searching for copper wire to trade for pocket change.

The substation, which is across the street from the Randall Playground, is clearly marked with signs warning of the high-voltage wires. But a hole in the fence at ground level near the gate was large enough for a 6-foot-4, 200-pound reporter to climb through.

Heard said the hole probably was made by rescue workers, but it showed evidence of having been partially patched with wire in the past. Heard said he would suggest that the hole be repaired again.

In the brush behind the substation, an empty, red-handled shopping cart, perhaps Edmondson's, was shoved into the weeds.

Staff writers DeNeen L. Brown and Martin Weil contributed to this report.