Eight minutes after Amtrak's "Caucus Special" pulled out of Union Station Saturday morning, Jason Slattery, 7, posed the inevitable child's question to his father, Rep. James C. Slattery (D-Kan.).

"Daddy, are we almost finished with our ride?"

The answer was no, but Jason and his fellow passengers -- including 106 Democratic House members, about 75 of their spouses and more than 100 children -- had little to complain about.

With the passenger-railroad agency once again on President Reagan's budget chopping block, the 18-car "Caucus Special," with its several open bars and observation car from which lawmakers could view the passing mountain scenery, was everything an Amtrak lobbyist could hope for.

The House Democrats complain about their relative powerlessness while the Republicans control the White House and the Senate, but on Saturday they made at least one train run on time.

Their destination was the sprawling Greenbrier resort here in the mountains of West Virginia, where they were supposed to hold a serious discussion of national issues amid a seemingly limitless array of distractions -- the hot baths and massages, swimming, tennis, bowling, movie theater, shops and, of course, the daily afternoon ritual of "high tea."

The stately white buildings of the Greenbrier, set amid the impeccably kept 6,500-acre grounds, are a long way from what the Democrats like to think of as their gritty, blue-collar heritage.

There were also inevitable comparisons with the House Republicans, who chose the same weekend to meet in Baltimore, which is as much a symbol of working-class values as the Greenbrier is of wealth and privilege.

"We Democrats once a year come here to see how the fat cat Republicans live," said Rep. Tony Coelho (Calif.) in a typical response to this symbolic turnabout for the Democrats.

"It's kind of pleasant living here."

Indeed it is, so pleasant that the Greenbrier Issues Conference -- this was the second -- is probably going to become an annual affair for the House Democrats.

The weekend was more social than political, but politics was never too far from the surface. The presumed future top leaders of the House -- Majority Leader James C. Wright Jr. (Tex.), who is expected to succeed retiring Speaker Thomas P. (Tip) O'Neill Jr. (Mass.) next year, and Majority Whip Thomas S. Foley (Wash.), in line to replace Wright -- played prominent roles.

So did some of the younger lawmakers, such as Coelho and Steny Hoyer (Md.), who are jockeying to move up the House leadership ladder.

The lawmakers, their spouses and children were accompanied to the Greenbrier by two other groups. One was the "sponsors," the representatives of corporate donors who picked up the bulk of the estimated $200,000 bill for the weekend through contributions to the Democratic-controlled National Legislative Education Foundation.

Not all of these corporate lobbyists were known as lifelong friends of the Democrats.

Looking over the crowd at the Saturday night dinner, Rep. Jack Brooks (Tex.) grumbled, "I've seen people here who haven't voted for a Democrat ever."

The other group was the press, which was barred from attending the first Greenbrier conference last year but managed to cover it from the outside.

Faced with unsettling comparisons between their plush weekend retreat and the GOP meeting in Baltimore, the Democrats decided the last thing they needed was a suggestion that they were holding a "secret meeting" in an exclusive resort.

"The entire conference is open to press coverage," Foley announced on the train.

"Well, could we petition for a change in that policy?" replied one of the many reporters who brought along a tennis racket.

The least-covered event was something called a "Fun Run," which Caucus Chairman Richard A. Gephardt (Mo.), a running enthusiast, scheduled for 7 a.m. Saturday.

ABC News reportedly sent a camera crew to record the event, and about six lawmakers were said to have participated.

None of this information was independently confirmed, however, because the rest of the press corps followed the lead of Cokie Roberts of National Public Radio.

"I'm planning on a Fun Sleep," she said.

The unseen but most pervasive presence at the Greenbrier was that of a former Democrat -- Sen. Phil Gramm, Republican of Texas.

Gramm, along with Sens. Warren Rudman (R-N.H.) and Ernest Hollings (D-S.C.), is the author of the dreaded Gramm-Rudman-Hollings balanced-budget law, a dominant topic of coversation.

On Saturday night, when the House Democrats provided their own entertainment, they still had Gramm on their minds.

Rep. Dan Glickman (Kan.) sang an off-key melody of "Fools on the Hill," recounting passage of the bill.

Rep. Marvin Leath (Tex.), dressed all in black, said, "Here's something Rudman was heard to say to Gramm the other day" before launching into a rendition of "Let's Go Out in a Blaze of Glory, All Good Things Must Come to an End."

But the highlight was provided by three female lawmakers -- Marcy Kaptur and Mary Rose Oakar of Ohio and Barbara Boxer of California.

To the tune of "The Way We Were," they sang:

"Memories, of the days before Phil Gramm, lovely budget spending memories, of the way we were."

There was more than a little truth in this sad lament about the lost days of big-spending domestic programs, but the Democrats, who said their spirits were on the rise, at least were able to laugh about it.