In the midst of the Great Blizzard 10 days ago, planes did not fly, highways were barricaded by snowdrifts and transit systems from Washington to Boston did not operate. Almost everything stopped.

Amtrak kept on training.

"If anybody had to get to New York in an emergency, there was no way they were going to get there except on our railroad," Amtrak President W. Graham Claytor Jr. said, with obvious delight.

"It just couldn't have been done, no matter what the urgency . . . . I think Amtrak's here to stay."

That appears to be the case, perhaps for the first time since the National Railroad Passenger Corp. (Amtrak's real name) was formed in 1971, and despite criticism from sources as varied as the Congressional Budget Office and the conservative Heritage Foundation.

The quality of service is better, a remarkable contract has been signed with engineers and conductors that eliminates some of railway labor's most hallowed and least defensible traditions and the railroad is meeting at least half of its costs from fares.

Senate Commerce Committee Chairman Bob Packwood (R-Ore.), one of those who oversee Amtrak, said that "with the new equipment, Amtrak has simply gotten more efficient. With Graham Claytor, they have the right guy in the right place at the right time."

Amtrak has always had public support, Packwood said, while justifying costs has been somewhat difficult politically. Now, he said, "there is some substantive basis" for doing so.

Taxpayers have spent at least $8.5 billion on Amtrak since they bought it, including $2 billion to rebuild track and stations on the so-called Northeast Corridor between Washington and Boston.

According to a "performance evaluation report" Amtrak issued at the end of fiscal 1982:

* Passenger complaints dropped from 25.2 per 10,000 riders in 1979 to 12 per 10,000 riders in 1982.

* In 1979, only 57 percent of Amtrak's trains ran on time. In 1982, it was 79.1 percent. On-time performance is defined as being no more than five minutes late for every 100 miles traveled, to a maximum of 30 minutes late.

* Air-conditioning failures on Amtrak trains dropped from 2,207 in 1978 to 153 in 1982.

* More than 85 percent of phone calls to Amtrak are answered within 20 seconds, and only 1 percent are lost. In late 1981, before a new computer was tamed, about 40 percent of all calls were "lost."

* Taxpayers get more for their dollars. In 1979, Amtrak carried 4.3 passengers one mile for every federal dollar; in 1982, it was 5.3 passengers, and in 1983, it is expected to be 6.7.

* Northeast Corridor improvements have returned the whoosh to Metroliners. They travel from Washington to New York in 2 hours, 49 minutes on a much smoother track. Metroliners run at 110 mph for as long as 30 minutes at a time. Next year, Claytor said, they will reach 120 mph.

Despite the good signs, Amtrak ridership dropped last year from 20.6 million passengers to 19 million. The decline is attributed to the recession, which has hit hard at transportation operations, to fare increases needed to maintain Amtrak revenues and to competition from airlines, which showed a slight increase in passengers in 1982 after a disastrous 1981.

Nonetheless, Amtrak carried more passengers last year than TWA or Republic and was bested only by Eastern, Delta, United and American.

Although some parts of the country, especially in the Midwest and Southwest, have no passenger service, Amtrak operates 230 trains daily over 23,000 route miles reaching 500 towns and cities, including all of the 29 with a population of 1 million or more.

Ross Capon, president of a cheering squad called the National Association of Railroad Passengers, has fought furiously for Amtrak appropriations and has been one of Amtrak's severest critics on questions of service.

"They have achieved a better consistency of service quality than ever before," Capon said. " . . . The debate is no longer over whether we need to have Amtrak . . . . So the dimensions of the attack have diminished."

President Reagan's new budget contains none of the anti-Amtrak rhetoric, for example, by Office of Management and Budget Director David A. Stockman, who wrote two years ago: "Passenger trains, while part of the country's heritage and history, have little place in a federal budget which is heavily in deficit."

For fiscal 1984, the administration has proposed $676 million in outlays for Amtrak, a drop of $24 million, plus $310 million for continuation of the Northeast Corridor improvement project.

Claytor said that his budget proposal, which he is to submit to Congress this week, will be somewhat higher, but that the administration proposal is "in the ballpark with what we will have."

In 1979, Congress established criteria for determining which routes and trains Amtrak should retain. In effect, Congress was disciplining itself, because nothing is tougher for a congressman than admitting that the train through his district is dispensable.

Using the new criteria, Capon said, Amtrak by 1981 no longer had to run "the last of the true dogs. The system that remains is actually performing well or has that potential."

Claytor agreed. Only the Cardinal, from Washington and New York through West Virginia to Cincinnati and Chicago, remains on the administration's "hit list" because it does not meet performance standards. But the Cardinal has the support of Senate Minority Leader Robert C. Byrd (D-W.Va.), who still praises it as the greatest thing on wheels.

Claytor's view is that "the Cardinal has been significantly improving each year. I think the Cardinal's probably all right, and I think Congress is going to make it stay anyway."

Claytor and his immediate predecessor, Alan Boyd, the first transportation secretary, have given Amtrak quality leadership at a critical time. Capon said Boyd brought political skills to the job when they were most needed, during the redefinition of Amtrak's route structure and cost assumptions.

Claytor, no mean politician himself as former deputy secretary of defense, knows railroads and, unlike many railroaders, likes passengers.

The Southern Crescent to New Orleans was the last great private enterprise passenger train, and Claytor, as president of the Southern Railway, kept it running, even though it was losing money, for some years. "What we got out of it," he said, "was a good deal of favorable comment, publicity and good will."

Claytor arrived at just the right time to take advantage of huge purchases of new equipment and improved track in the Northeast.

"Every single thing we are running today is either not more than six years old or has been completely rebuilt with electrically powered heating and air conditioning," he said. " . . . We've gotten rid of the combination of steam heat and batteries. They're gone. That just makes all the difference in the world."

Coupled with the new equipment are new labor contracts. In January, for the first time, Amtrak began directly employing engineers, conductors and train service employes for its trains in the Northeast Corridor.

In the past, Amtrak had contracted for them from federally owned Conrail and its predecessor railroads, a practice it continues in other sections of the country where Amtrak trains run on somebody else's track.

The significant difference between the new Amtrak contracts and traditional railroad labor agreements is that engineers and conductors are paid for an eight-hour day and a 40-hour week.

They had been paid on a mileage-based formula rooted in the slow trains of history. It said, in effect, that 100 miles was a day's work, and many engineers worked 11 days and got a month's pay.

Amtrak agreed to phase in the new pay schedule over three years. "If a fellow has been getting a week's pay for two days' work on Monday and the next Monday he's going to have to work five days for the same pay, this is sort of a shock, it's hard to sell," Claytor said.

Because of the contract, Claytor figures he will need one-third fewer engineers. But he declined to predict precisely how much money can be saved until he has had a year's experience with the new contracts.

Claytor talks about train movements and other operating details with the same enthusiasm as a dispatcher in the tower. He took a strong personal hand in the blizzard operation and insisted that all available equipment be run.

Metroliners were canceled and combined into other Northeast Corridor trains so that faster trains would not overtake slower ones and require substantial switching, a problem in heavy snow. For the same reason, freights were canceled.

Amtrak ridership in the Northeast Corridor increased 25 to 30 percent over the snowbound weekend, despite a trackside fire in Connecticut that closed the railroad for three hours and an office building fire in Chicago that silenced a phone-in reservation center for two hours.

Amtrak came of age, Claytor said, when it became an owner of track--the Northeast Corridor in 1977--instead of just a contractor buying services from other railroads.

"The people who are running Amtrak now are railroad people," he said. "It's not a debating society or just another government agency. I think it's helped a great deal . . . . We are recognized now as another railroad, not as those silly people who are trying to run trains over our railroad.

"One other thing that's helped us is that business is so bad. I've had one or two railroad presidents say, only half in jest, 'Can't you guys run a couple of more trains over our railroad; it's the only thing we're making money on.' "