Here they came, strolling across the Roberto Clemente Bridge that spans the Allegheny River downtown, under the late afternoon sun, in sporadic twos and threes, a trickle of early-arrivers, on their way to sip happy-hour beers or watch batting practice. And here they came still, in the early evening shadows just before first pitch, a teeming flood now of yellow-and-black-clad humanity, funneling in and filling every square inch of their waterfront baseball palace.

For years, PNC Park was the saddest place in baseball — a gorgeous new ballpark, as picturesque as any in the game, that most nights sat half-empty or worse while the hopeless Pittsburgh Pirates lurched toward yet another season of sub-.500 irrelevancy. Babies were born, graduated high school and went off to college without knowing the thrill of a winning Pirates team.

But this summer — well, dare we say it? For 16 weeks now, the hard-core have seen their faith rewarded, the fair-weather fans have flocked back, and even the scarred-for-life fatalists are letting themselves believe again. And they’re all coming together on warm summer nights to pack PNC Park on a regular basis and root on a Pirates team that has ranked as one of the best in the game all season.

“It’s a great baseball town,” said Bob Walk, the Pirates’ longtime radio broadcaster. “Like anyplace else, if you have year after year after year of losing baseball, then all you’ve got left is that hard core of fans that’s sticking it out. But this is awesome. This is the way baseball should be here — the way it used to be.”

On October 14, 1992, Walk, a right-handed pitcher, was warming up in the Pirates’ bullpen in the ninth inning of Game 7 of the National League Championship Series when teammate Stan Belinda threw the fateful 2-1 pitch that Atlanta Braves backup catcher Francisco Cabrera lashed into left field for a single — and when Braves base runner Sid Bream slid home ahead of left fielder Barry Bonds’s desperation throw, the Braves went to the World Series and the stunned Pirates went packing for the winter.

Little did anyone know that 21 years later, those 1992 Pirates — of Bonds, Andy Van Slyke and Doug Drabek, a group that had produced three straight division titles — would still stand as the last winning team in Pirates history.

“Nobody could have seen this coming,” Walk said. “Twenty years? That’s unfathomable.”

The team’s slow build

Of those 20 losing seasons that followed, none have been more painful than the three-year stretch that preceded 2013. There was the 105-loss fiasco in 2010, the worst Pirates team in more than half a century. There was the wicked tease of 2011, when they were tied for first place in late July only to crash down the stretch to finish with 90 losses. And there was the even more gruesome collapse of 2012, when they held the wild-card lead well into August but went a staggering 16-36 over the final eight weeks to finish in fourth place at 79-83.

But even as the streak grew — becoming the longest string of losing seasons in American professional sports history — people in the industry understood the Pirates were a sleeping giant, thanks to a stockpile of young talent harvested from all those high draft picks over the years (Andrew McCutchen, Neil Walker, Pedro Alvarez), plus a series of shrewd moves by the front office to target reclamation projects (Jason Grilli, A.J. Burnett).

After adding pieces such as lefties Wandy Rodriguez and Francisco Liriano and catcher Russell Martin between July 2012 and February 2013, the Pirates had the look of a legitimate contender entering the 2013 season. In late June, they became the first team in baseball to reach the 50-win mark, and last week they sent five players to the All-Star Game in New York, their most since 1972.

“You look at those men, look at the skill sets — we’ve got enough talent out there,” said third-year Manager Clint Hurdle, who presided over the second-half collapses in 2011 and 2012. “They’ve paid attention, learned some valuable lessons. I think we got distracted at times. There’s a level of mental toughness that comes with the finish. There’s a level of physical toughness and endurance. I think we’ve learned. We’ve added some layers of toughness.”

One unfortunate consequence of all the losing is a sense of impending doom among the media and fans, the feeling of “here we go again” that manifests itself, quite understandably, anytime the team loses a few games in a row, as it has a couple of times over the past few weeks.

“We understand it,” General Manager Neal Huntington said. “We understand the anger of being under .500 for so many years. To hear the anger when we didn’t make the playoffs a year ago is actually a good thing because it means there is still passion.”

The men in the Pirates’ clubhouse, most of them responsible for only a handful of those 20 losing seasons, also understand the fans’ sense of fatalism. “They don’t have any reason to not feel that way,” said Grilli, the closer who became a first-time all-star this year at age 36. “The only way to change that mind-set is to win.”

The fans’ return

To see PNC Park jampacked and boisterous in the summer of 2013 is to flip backward through a history book, skipping the awful two-decade stretch of losing and going back to the time when Pittsburgh was one of the best baseball towns in America and the Pirates were one of the jewels of the game. This is a franchise that has won more 10,000 games in its history and produced seven division titles and three World Series championships between 1960 and 1979.

“This is a proud sports town, and the last 20 years have been like a black eye,” Hurdle said. “But we have a chance here to re-bond a city with its baseball team.”

The days of the Pirates ruling Pittsburgh’s sports scene are probably gone for good, with the Steelers — the dominant franchise in town — growing into a dynasty in the 1970s and remaining a perennial Super Bowl contender today, and the Sidney Crosby-era Penguins becoming one of the NHL’s most consistent winners.

But this year’s Pirates team seems to have rekindled a flame buried so far deep in the soul of Pittsburgh, many younger fans may not have known it was ever there.

“There’s always a little part of you that says, ‘It’s not going to happen — again,’ ” said Ryan Seymour, 28, a fan from West Mifflin, Pa., who proudly shows off his three prized tattoos: the logos of the Penguins, Steelers and Pirates. “But I believe this is going to be the year.”

On the Tuesday before the All-Star Game, Chris Policicchio, 38, of Gibsonia, Pa., walked from his downtown job across the Clemente Bridge and saw the Pirates lose a 2-1 decision to Oakland. Near the end of the game, he walked up to the advance ticket window, as he had done many times before, to buy a pair for the game that Friday night — only to draw a disdainful glare from the man behind the window.

“He looked at me like I’m an idiot,” Policicchio said. “The game was already sold out.”

So Policicchio went to and bought a pair for above face value.

“Things have felt hopeless around here until last year — and then the collapse was just horrible,” he said. “But if they keep getting deeper each year, it’ll happen. I just feel like this year is different. This year, they’re the real deal.”

If you’re a Pirates fan who has lived more than half your life without a winner, you want to believe this year is different. But is it? Before Sunday’s win in Cincinnati, the Pirates had lost three straight and seven of their last 10. Was another collapse taking shape? Could this city — could these fans — survive another?

And so, as August approaches — with its promise, across this land, of a thrilling stretch run toward October — take a pause in the noble cause of rooting home your own team, no matter how starved for a winner you may be, and send some warm thoughts toward your Pittsburgh brethren, that they may know, for the first time in two decades, what it feels like to love a winner.