A subway supervisor and a train operator failed to take any of several corrective steps that could have averted last week's fatal wreck in which three passengers were killed and 25 others injured, Metro officials announced yesterday.

The officials said that human errors--including failure to correctly align a switch, failure to stop at a red light and failure to halt a slowly moving train that was derailed and headed in the wrong direction--caused a crowded train to be slowly dragged backward along two parallel tracks for 13 seconds until one car was pushed into a concrete abutment separating the tracks.

Metro General Manager Richard S. Page termed the accident, which occurred about 4:30 p.m. on Jan. 13 near the Smithsonian station and involved an Orange Line train bound for New Carrollton, "a fluke" and said the odds against "this strange set of circumstances" occurring again are "overwhelming."

Page said the accident, the first fatal crash since the subway opened in 1976, would prompt Metro officials to pay more attention to operating procedures on the subway, and he expressed his regrets to the victims and their families. Metro officials also said they would increase the quality and amount of training for subway operators and supervisors.

The information was released at a Metro press conference yesterday as part of the preliminary conclusions of separate investigations by Metro, the American Public Transit Association and the National Transportation Safety Board.

The subway car operator and the supervisor have been placed on administrative leave during the investigations, which may take months to conclude, Metro officials said. In the meantime, they have refused to identify either of the employes.

Problems for Metro had been mounting all afternoon on the day of the crash, Page said. The federal government, against Metro's advice, released its workers early because of a heavy snowstorm. Metro was caught with a rush-hour situation while operating on a nonrush-hour schedule, and trains were jammed by 1:30 p.m., Page said.

As outbound trains backed up at the Smithsonian station, Metro's command center, whose computers control the flow of subway traffic, routed several trains around the congested area by crossing them over temporarily to tracks ordinarily used by trains going in the opposite direction.

After several trains had been rerouted, the command center attempted to reset the switches--which reroute the trains to another track--to their normal positions.

At that point, Page said, computers at the command center indicated that one switch had malfunctioned, and the controllers told a supervisor near the scene to inspect four switches at crossover tracks near the Smithsonian station and, if necessary, reset them by hand.

A tape recording of a conversation between the supervisor and central control indicated that the supervisor had reported checking all four switches and placing blocks of wood in them to ensure proper operation, Page said.

One switch, however, was not in the correct position nor was it blocked. "He may have thought he had done it, or he may not have gotten to it," Page said.

As the train approached the crossover section, red lights were on, indicating that the switches were not properly set, Page said. But the train did not stop in accordance with Metro operating procedures, he said. Instead, the supervisor apparently waved the operator on.

The train began crossing over to the other track and at that point, Page said, the operator should have realized something was wrong and stopped the train. "An operator is supposed to know his route," he said.

Page said the tape recording indicates that the supervisor began shouting, "Hold it, hold it" as he saw the train headed toward the wrong track. But by the time the train operator stopped, the front wheels of the lead car had already jumped onto the wrong tracks.

The supervisor then boarded the train and, with the front wheels on the wrong track and the others on the correct track, began to back it up, operating from the rear car, Page said. The train derailed immediately, and the front wheels fell into the roadbed.

For the next 13 seconds, the train, straddling the two tracks, was drawn backward, with the lead car reaching a speed of about 8 mph, Page said yesterday. The train traveled about 60 yards before the car slammed into a concrete abutment dividing the two tracks. One wall of the car was crushed, two passengers were killed on impact and a third died of injuries a few hours later.

Page said the operator should have noted that the switches on each track were not in conformance as he passed over them. The operator also could have overridden the supervisor and stopped the train during its backward movement, when it derailed.

"There was nothing as far as we can tell to stop the movement of that train as it was being taken back toward the abutment," Page said.

Page issued new instructions this week designed to avoid these mistakes, and pledged there would be greater vigilance about procedures.