The bus had been filled with cigarette and beer fumes, raucus laughter, catcalls, dirty poems and frequent renditions of "Solidarity Forever" -- once the words were remembered. But by late Saturday night it was silent as the 36 weary marchers from Pittsburgh's Steelworkers Local 1408 digested their first real meal in 24 hours and reflected on their march on Washington.

Simply by participating in Solidarity Day, along with 260,000 other marchers, they had been labeled as "protestors." The comparison to the anti-war demonstrators of old, coupled with the vehement anti-President Reagan tone of the white-collar unions, had made them uncomfortable all day.

Suddenly, someone started singing "My Country 'Tis of Thee," and for the first time in this odyssey, the mood turned solemn. Before the song had ended, the entire contingent had joined in, transforming the patriotic anthem into a song of atonement.

Trailways Bus No. 29520 was one of thousands carrying protestors responding to a nation-wide call for labor solidarity this weekend. The message organizers hoped to convey was echoed by the lyrics of a popular rock song that played throughout the day: "We are Family." Yet, in reality, the reasons for the turnout were varied. In Local 1408, for instance, there was little anti-Reagan sentiment.

In McKeesport, outside Pittsburgh, where Local 1408 represents 4,200 workers of U.S. Steel's mile-long National and Duquesne works, sons still follow their fathers into the mills. This part of the Monongahela River Valley is heavily eastern European and has always been a linchpin of American unionism, a routine stop for national politicians.

All the same, a mere 36 workers -- mostly pensioners and union officials -- were all the valley's second largest local could muster.

Most of the 36 were long-time unionists in their late 50s. The pensioners and two janitors were allowed on the free trip because rank-and-filers didn't sign up for the seats. Only five of the union members were under 40, including one woman, and several of those showed up more out of loyalty to the principles of the Socialist Workers Party -- which several support -- than to their local. Two seats were filled by citizen activists from the Pennsylvania Public Interest coalition, a group interested in plant closings.

The reasons for the turnout are varied but they present serious questions about the depth of labor's anti-Reagan sentiments.

For starters, the "mill hunks" at this fabricating plant are lucky: they make badly needed tubing for gas and oil wells, making this 70-year-old plant one of two in the valley making money.

In this way Local 1408 is typical of most unions in this country: Its members are working, and they are earning an hourly average of $11.06, one of the highest industrial wages in the United States. Even if the fear of layoffs is never far from their minds, the attitude expressed by Eddy Ferencak, 24, dominates among those on the bus.

"Most people aren't worried about solidarity or unions. When they hand you the pink slip, that's when you'll see activity. That's the American way of life. It's happening to someone else, not to me."

Additionally, many of them voted for Ronald Reagan and few are able to say how he's wronged them less than a year later. "I still maintain White House Chief of Staff James A. Baker and presidential counselor Edwin Meese are making all the bullets and making Reagan shoot," said James L. O'Brien, 77, a retired crane man.

Richard Grace, union president, said, "Call it complacency, I guess. Everyone's satisfied. My mother in-law works as a senior health aide and she got laid off this week, so I know the Reagan budget can hurt."

Many of those complacent rank-and-filers filled the Beer Barrel, an unmarked bar next to the union hall, Friday night. None planned to make the free trip to Washington.

"I just now heard of Solidarity Day," said laborer Sharon Beresford, 29. "I thought they were talking about Poland." Her work partner, Rick Kruszyna, 25, added, "The union's very removed from me. We don't even vote on our contract any more. Our delegates vote for us in Atlantic City or somewhere." Unions are "just a place to hold a summer picnic," he said.

The younger workers drifted out and in walked two pensioners already set for the 2 a.m. departure. William "Maggie" Mayernick, a white-haired Slovak, and his buddy Samuel Tater, drank "shooters," a shot of whiskey and Iron City beer. The last time Mayernick went to Washington was during the Depression to protest about that "goddamn Hoover." He was now giving up a night of sleep to complain about Reagan's desire to knock off his Social Security raise.

A fellow unionist snorted at Mayernick. "Reagan's making sure our country isn't a sissy again," said Haven Stanley Jr., 37 whose two sons are joining the Marines this year. "These demonstrators are a bunch of foolishness and I don't like my union dues to be used for this."

Next door, in the union basement, a few yards from aging autographed photographs of FDR, Truman, Johnson and Kennedy, sat Chris Homme, 36, listening to Jimi Hendrix through radio earphones while waiting for the bus. "Maybe this will be a real revitalization of the labor movement. Maybe the '60s aren't dead."

His friend, Mark Zola, 37, a veteran of organizing anti-war bus trips, said he spent hours trying to convince others in the machine shop to attend. "Working people feel very powerless in affecting Washington and it shows in the cynicism around elections. The whole Solidarity Day will be a shot in the arm."

Zola feels so strongly about trade unionism that he and his wife, a blast-furnace worker, are driving to Toronto to begin a one-week Caribbean vacation instead of flying with non-union controllers from an American airport. Zola said he was motivated to attend the rally for fear Reagan will stop Trade Adjustment Allowance checks and worker health protections.

But most of the other riders had no issues on which to seize. The trip was a union obligation, a preventive move in case Reagan might do something to affect them. They expect the rally to bring them renewed respect, a brief return to the glory days when the world paid more attention to unionists. The mood resembled a fraternity outing.

The first item loaded on a bus was a trash can stocked with cases of beer. After pulling away from the mist-covered steel mill parking lot it was time for fresh beers and stale jokes, punctuated only by excitement over the growing number of bus caravans joining them in the darkness towards Washington.

A 4:30 a.m. stop in the truckers' haven of Breezewood, Pa., gateway to the south, brought more elation over the number of buses, as marchers from Cleveland, Iowa City, Lansing and Indianapolis clogged the restaurants in a scramble for coffee. The merry pranksters from McKeesport sobered up during their hour-long wait for food.

The steelworkers were anxious to don their white-and-black union T-shirts and head for the mall when they arrived at RFK Stadium at 8:10 a.m. After marveling at Washington's subway, they walked in the surge of other, bigger groups of unions looking for their alloted space just south of the White House on the Ellipse. At least half got lost in the confusion. It took over an hour, but the 36 regrouped.

By noon it was clear that the streets were too clogged with other unions and their excitement quickly wore down to exhaustion as they stood with several thousand others on the Ellipse.

Finally at 2:30 p.m., two-and-a-half hours behind the leaders, the Ellipse crowd around them began to move toward Constitution Ave. "We'll show Reagan!" laughed Don (Mimi) Marghotti, as he helped a friend to his feet. " -- That is, if he's still awake."

All were soon buoyed by their 15 minutes of glory -- marching in the enthusiastic press of unionists of every description who bellowed cheers like "AFL-CIO, Ronald Reagan's got to go." Local 1408ers didn't join in the chants, but carried a red Steelworkers district banner printed "We are against Reagan's union busting techniques."

"This is wonderful," said diminutive Rocky Doratio, 76, who retired four years ago after a lifetime in the mill. "You've got to let people know you're alive."

By 3:20 p.m. after three blocks of marching, union president Grace decided the point was made and ordered the troops back to the bus.

"This man Reagan is promising you the moon at the same time he's cutting your legs off," said Frank Kolich, one of the pensioners who, before he left McKeesport, said he voted for Reagan and would do so again. Now as he stood waiting for the bus, he said, "I'm afraid he's going to be a one-term president."

With a sense of achievement, the steelworkers reclaimed their bus, opened the remaining beers and directed the bus through the streets of Washington for 45 minutes until their destination was clear: they were looking for one of Washington's liquor discount warehouses. After 30 minutes of buying low-cost liquor, they were ready to head for home.