Transportation Secretary Brock Adams asked Congress yesterday to spend $52 million more to make Union Station work because the $46 million already spent has not done the job.

"This is a mess and I am not here to say who did it or how it was done," Adams told the House Public Works Subcommittee on Public Buildings and Grounds. "My job is to fix it."

"We have had 10 years of disaster at Union Station," said Rep. Norman Y. Minetta (D-Calif.), the subcommittee chairman. "There is more than enough blame to go around."

With the question of blame thus set aside, Adams said that it would take at least $34 million to keep the present Union Station-National Visitor Center standing even if nothing were done to improve a situation that has brought wrath from both rail travelers and architecture critics.

Adams' proposal yesterday was one of the results of an agreement he and Interior Secretary Cecil D. Andrus struck last July to solve the Union Station problem. The old classic Union Station actually belongs to Interior, and is referred to as the National Visitor Center. Trains don't come there any more.

The National Visitor Center is carpeted and has a large multiprojector slide show in the middle of a hole in the flour. Few visitors to Washington see the slide show, partly because the 1,200-car parking garage that started as a 4,000-car parking garage adjacent to the station has never been completed.

The railroad station, which serves various Amtrak trains, including the Metroliners, and an ever-increasing number of commuters on three commuter lines from Maryland, is relegated to a small, motel-lobby-like structure in back of the grand old building.It is one-third of a mile from the front of the Visitors Center to the train platforms.

Adams and Andrus agreed in principle that much of the original station should be returned to railroad purposes, although the hole in the floor and other National Visitor Center activities would stay in the main lobby. The Transportation Department would run the building.

Andrus joined Adams at the hearing yesterday and said he supported the transfer. "We would like to bring this to a completion," he said. However, he added, if the rent to the Interior Department for Visitor Center facilities exceeds $1 million a year, "we would prefer to withdraw and have (the building be) totally a transportation facility."

It was learned outside the hearing room that there have been intense negotiations among staff members of Transportation and Interior, and that a major sticking point in a unified administration position has been the rent that Transportation would charge Interior.

Part of Adam's proposal would restore railroad ticketing and waiting areas to the old terminal designed by architect Daniel Burnham. The motel-like station would be abandoned.

But people coming into the station from the front could not go directly to the trains because of the hole in the floor. Adams tried to explain that to subcommittee members. "You have to go through . . ." he said, then stopped and made a large gesture indicating a depression.

"How are we going to get that in the record?" Minetta asked, making the same gesture.

"You have to go through (pause) the pit," Adams said.

Adams' press secretary, David Jewell, flinched. "I told him not to say pit," Jewell said in an aside to the press table. "It makes them mad." Them is the Interior Department.

It is the pit that most offends architecture critics, who recall the grand expanse of the old station with longing.

Under Adams' proposal, the parking garage would be completed, as would a connecting ramp along the north and east sides of the station. That would permit easier bus and auto access.

Adams conceded yesterday that his proposal did not include provisions for the intercity bus lines such as Greyhound and Continental Trailways. That was part of the original proposal to turn Union Station into a Visitor Center and transportation complex.

James L. Kerrington, Greyhound vice chairman, testified that "Congress should not accept any compromise that would permit rail expansion in the present Union Station and ignore or defer inclusion of the intercity bus facilities . . ."

Construction of the Union Station-Visitor Center complex was halted in 1976 when the money ran out, largely because of huge overruns on the still uncompleted and unused parking garage.

"Wouldn't it be better to start all over rather than dump more money into this mess?" Rep. William F. Walsh (R-N.Y.) asked Adams. "Do you think it's worth it?"

"Yes," said Adams. CAPTION: Picture 1, BROCK ADAMS . . . asks for $52 million more; Picture 2, The Visitor Center, This picture of the National Visitors Center was taken when it opened in July 1976. It shows the pit, a sunken area that features a slide show. By Tom Allen - The Washington Post; Picture 3, The Rail Station, The new railroad station ticket and waiting area opened in August 1976 and is a third of a mile from the entrance to the Visitor Center., By Gerald Martineau - The Washington Post; Picture 4, Secretary of Transportation Brock Adams huddles with aides during testimony on making Union Station work., By James K.W. Atherton - The Washington Post; Picture 5, REP. NORMAN Y. MINETTA . . . "10 years of disaster"