An article Friday identified Amtrak President W. Graham Claytor Jr. as a former secretary of the Army. He is a former secretary of the Navy.

Diana McGrevy, sitting in the club car of Amtrak's Cardinal as it raced toward West Virginia's spectacular New River Gorge, said she is unemployed and rode the train from Washington to Cincinnati because the round trip cost $95, while the least-expensive, short-notice airline ticket was $250.

Her choice of a 13 1/2-hour train ride is part of an emerging transportation policy debate between two of the best advocates in town: Office of Management and Budget Director David A. Stockman, who has proposed eliminating all federal money for Amtrak effective Oct. 1, and Amtrak President W. Graham Claytor Jr., who is fighting back with arguments not just about money but about social class.

Claytor won the first round yesterday when the Senate Budget Committee voted the same amount of money for Amtrak in fiscal 1986 that it is getting this year: $684 million, a figure matching Claytor's request.

"In a country this big, what are you going to do if you don't drive your own automobile and you don't want to spend 24 hours on a bus?" Claytor asked in an interview. "There's no other way to go except to fly. There are a hell of a lot of people who can't fly for health reasons, and an even larger number who won't fly because they don't like it. You're going to leave those people without any form of transportation."

Transportation Secretary Elizabeth Hanford Dole, however, told a House subcommittee that "Amtrak provides only 2 percent of intercity travel [automobiles] provide about 80 percent ." On Amtrak's Northeast Corridor, from Boston to Washington, "55 percent of the passengers have incomes of more than $30,000," Dole said. "We have to look at where the priorities are. It's so heavily subsidized."

The corridor carried half of Amtrak's 20 million annual passengers, but provided only one-third of last year's operating revenue of $758.8 million because the fares are less for the northeast's shorter trips.

Nationwide, Claytor said, 47 percent of his riders have family incomes of less than $20,000, more than one-third of his passengers are 55 or older, and only 20 percent of his passengers are on business trips.

If Congress adopts President Reagan's budget, the Cardinal and Amtrak's 249 other trains will cease to operate, Claytor said. The Transportation Department challenges that, but if Claytor is right, on Oct. 1, when fiscal 1986 arrives, this would happen:

* 135,000 weekday commuters whose non-Amtrak trains run on Amtrak's track would be stranded on the Northeast Corridor, unless the states, transit authorities and freight railroads came up with about $212 million to keep the track, signals and stations in operation.

* 17,500 daily passengers who use Amtrak between and among Washington, Baltimore, Wilmington, Philadelphia, Newark and New York would have to fly, drive or take the bus, adding traffic to busy airports and freeways.

* 2,700 passengers who use Amtrak between Washington and New York would have to find other transportation.

* Thousands of passengers who depend on trains at 500 stations from Albany, Ore., to Yemassee, S.C., would have to switch to buses, autos, airplanes or some combination of them. A total of 21 communities that Amtrak serves would be without scheduled bus, rail or air service.

* 25,000 railroad employes -- 21,000 of them at Amtrak -- would be laid off, creating a potential $2.1 billion liability against Amtrak for federally mandated labor protection. Amtrak's stock is owned by the federal government.

Reagan said in his State of the Union message that "Taxpayers pay about $35 per passenger every time an Amtrak train leaves the station. It's time we ended this huge federal subsidy." That number is derived by dividing Amtrak's 20 million annual passengers into its $684 million federal subsidy. While the computation essentially is accurate, the results are deceptive.

Claytor, once the profit-oriented chairman of Southern Railway and a former secretary of the Army, defends Amtrak with the knowledge that all forms of transportation -- those needing red and green lights and those needing air traffic controllers -- are subsidized by taxpayers.

His political problem is that the Amtrak subsidy is easy to see in the budget and easier still to convert to a catch phrase. The difference between Amtrak and the airplane, Claytor said, "is that our people spend their own money to travel. Sixty-five percent of the major airline passengers travel on business and deduct it." When the tax deduction for a business expense is taken, he said, "it comes out to 33 bucks an airline passenger, which is almost the same . . . . The difference between not collecting tax money and paying tax money out is, it's the same dollar," Claytor said.

Secretary Dole attacked Claytor's $33 figure at a House hearing, saying, "That's a business tax deduction, not a subsidy."

But in the Senate, when she was defending the federal government's proposed sale of Conrail, the northeastern freight railroad, to Norfolk Southern Corp., she noted that Norfolk Southern will surrender many of Conrail's tax benefits and said "this represents true value to the treasury and is a very important element of the total compensation."

Amtrak collects almost 60 percent of its budget from passenger fares, a steadily improving portion, but there is a limit to how high fares can go, Claytor said. Since Claytor took over in 1981, Amtrak has shown steady operational as well as fiscal improvement.

Within the constraints of arcane railroad labor agreements, he has moved trains to more productive routes, improved on-time performance from 69 percent systemwide in 1980 to 80 percent last year, and increased the Metroliner's top speed to 120 mph to cut the time of New York-to-Washington trips from more than 3 hours to the current 2 hours, 49 minutes.

More than $2 billion has been spent repairing track and restoring the corridor's once-grand stations, from Washington's Union Station to New York's Penn Station, now getting a facelift to make it more pleasant for the passengers who use it daily on 750 commuter and Amtrak trains.

Trips on Amtrak's Cardinal between Alexandria, Va., and Charleston, W.Va., and on a New York-to-Washington Metroliner show the two faces of Amtrak. The former is the more leisurely people's train, favored by the elderly, families with small children, and blacks, particularly on trains to the South. The latter is also the Northeast businessman's special, complete with briefcases, three-piece suits, calculators and furrowed brows.

Trains are not the place to find people who think the government has no business subsidizing passenger railroads. Diana McGrevy, for example, finds it "unimaginable" that Amtrak service would end. Debbie Bates, who lives in Greenbelt, decided that driving two rambunctious youngsters to Charleston was not an appealing prospect. "It's just easier than flying with the kids. They can move around," she said. "I don't think they should get rid of it."

The Cardinal carried 224 people, including 91 eighth graders from Walnut Hills High School in Cincinnati, an academic public high school, returning home after a tour of Washington. "I love trains," teacher Gwen Walker said. Killing Amtrak "would be unfair. There are people who rely on it," she said.

Ernest and Jerry McCoy, a retired couple, boarded in Alexandria and were riding to Cincinnati. "We need this train," said Jerry McCoy, and "I don't like him President Reagan for" his proposal to cut the service.

The Cardinal arrived in Charleston 15 minutes late after making up five of 20 minutes lost at Clifton Forge, Va., in a futile attempt to fix the air conditioning on two cars.

The next day, the noon Metroliner from New York left punctually with 66 on board, including Conrad Johnson, a lobbyist from the national office of the Presbyterian Church in New York. He was on his way to Capitol Hill. "It is such a pain going to and from airports and fighting the cabs," he said. Amtrak's subsidy "is not a lot of money relative to the budget . . . . I don't think making all costs back is a requirement. It's not in European countries."

The train arrived on time at Union Station, three blocks from Claytor's office, where he is taking the threat to Amtrak seriously despite yesterday's victory in the Budget Committee.

Every president since Richard M. Nixon has attempted to kill Amtrak, but Congress always has found money for it even as it has required improved financial performance. Each battle has brought a new set of standards and sometimes more service cuts; five of the 48 contiguous states have no Amtrak trains.

Deputy Transportation Secretary James H. Burnley IV said in an interview that if Claytor "is able to curtail service on those lines in which he loses enormous amounts of money which is now made up by the American taxpayers, he can continue to operate those lines where he is generating enough in fares to cover his costs.

"Mr. Claytor needs to think about real world alternatives and spend less time contemplating earthquakes and floods, and we're more than willing to help him."

If he closes all of Amtrak but the trains running the Northeast Corridor, as the Transportation Department seems to be suggesting, Claytor says that would trigger labor protection costs for Amtrak jobs lost in the rest of the country that would exceed his revenue. "The only thing to do would be to declare bankruptcy, and a trustee would take over," he said.

Most trains in the corridor meet their daily operating costs, but fares do not pay for new or refurbished equipment or meet the costs of maintaining track and operating signals and yards, Claytor said.

"So there is absolutely nothing either a state or private business is going to take over or run," Claytor said. "There is no tooth fairy."