The administration scored a victory yesterday in the first major test of the Transportation Department's proposal to cut back on Amtrak's route system by 43 percent.

The Senate Commerce Committee voted to report to the Budget Committee that it estimates $552 million will be needed for Amtrak's operations in fiscal 1980 -- the reduced subsidy amount DOT says will be needed for the restructured national rail passenger system.

DOT says $718 million would be required if the present route structure was retained.

Although the budget estimate can change in the future if the Commerce Committee decides against the DOT plan, the vote yesterday offered an initial test of the senators' sentiment on test of the senators' sentiment on it.

The voice vote -- with just one voice audible in opposition -- followed a spirited debate on Amtrak, the routes scheduled for abandonment, and the federal role in keeping a national rail passenger system alive during an inflationary economy when there are pressures to balance the budget.

"I can't support a cutback in Amrak's route system in the absence of a national transportation policy," Sen. Barry Goldwater (R-Ariz.) complained. Without it, and with possible deregulation of other modes of transportation besides airlines, he said he was not sure the citizens of Arizona would have access to a national transportation system.

He was backed by Sen. Harrison Schmitt (R-N.M.) who said the country had not given modern rail transportation "a chance, not even experienced it."

Sen. John Danforth (R-Mo.) disagreed. "I think we've got a problem with our budget, and my view is the major cause of inflation is what we're doing right here: we're just spending too much darn money," he said.

The Congress started pumping money into Amtrak eight years ago, and the system isn't self-sufficient. "There have been no good arguments made for keeping these routes," he contended, saying that although 43 percent of Amtrak's trackage would be affected by the DOT plan, only 9 percent of Amtrak's riders would be.

Noting that only three-tenths of one percent of intercity passenger traffic uses the rails, Danforth said 9 percent of that number meant that only 27 people out of every 100,000 traveling between cities would be affected. (And $168 million in federal subsidy would be saved.)

"I just don't think we can throw away money like that," he argued.

Sen. Ernest Hollings (D-S.C.) also supported the cutback, even though three trains would be affected in his state, he said.

"Then let's stop Amtrack altogether or reduce all long hauls," Goldwater interjected. "If Amtrak keeps going on as it has, I may support him on that next year," Commerce Chairman Howard W. Cannon (D-Nev.) said noting that even if Amtrak ran full, "it would still lose money." For the subsidy paid to keep the New York-Florida run going, Cannon said the government could fly people and give them spending money and save.

In other action, the committee:

Voted to authorize a total of $500,000 for the Office of Rail Public Counsel in the Interstate Commerce Commission, instead of the $1.85 million requested, through fiscal 1980. Senators agreed with Sen. Russell Long (D-La.) that the office's activities in representing the public interest in the rail area should be picked up by the ICC's own public counsel's office, which deals with non-rail matters, after the smaller transitional budget they authorized.

Approved and sent to the Senate floor the nomination of Anne P. Jones to be a member of the Federal Communications Commission.

Agreed to waive an agreement signed voluntarily by Federal Trade Commission member Robert Pitofsky when he was confirmed last year to abstain from participation in three FTC proceedings. When a professor of law at Georgetown University, Pitofsky had served on the board of directors of a public interest group that filed several petitions with the FTC that involve the proceedings. The Justice Department told the committee that removing the ban would not place Pitofsky in violation of sound, conflict-of-interest priciples.