PITTSBURGH — The images are living, breathing blueprints for unprecedented and unparalleled success.

Franco Harris sprinting through the snow, the general of Franco’s Italian Army bound for glory. Jerome Bettis departing the station, shifting gears all the way as the Bus churns toward the end zone. Willie Parker all by his lonesome, a stunned defense in the wake of his blurring feet.

For more than two generations and a fistful (plus one) of Super Bowl trophies, the running game has defined the Pittsburgh Steelers, reflecting not just a city but a way of life and turning the guys standing next to the quarterback into one-named wonders.

Franco. Jerome. Willie. Barry. Bam.

Let other teams throw the ball around all around the lot. Not in Pittsburgh.

“Everybody is used to the ground-and-pound thing here,” running back Jonathan Dwyer said. “Real gritty.”

The last few years, however, the grit has been replaced by a grimace. Since the Steelers won their sixth Super Bowl in 2009, the running game coach Mike Tomlin talks about as the foundation of the franchise has disappeared.

Over the last four seasons, Pittsburgh ranks 23rd in 100-yard rushing games according to STATS LLC, having a back top the century mark just 12 times. That’s not exactly Steelers football. That’s more like flag football.

The nadir came in 2012, when the Steelers finished 26th in yards rushing, 27th in yards per carry and 27th in touchdowns rushing (eighth) as Dwyer, Rashard Mendenhall and Isaac Redman struggled. Dwyer’s team-high 623 yards were the lowest by the franchise’s leading rusher since Merril Hoge (610, 1990).

Pittsburgh missed the playoffs that season, just like it did last fall after going 8-8.

Having a potential Hall of Fame quarterback in his prime is a factor, yet even Ben Roethlisberger admits Pittsburgh has to get it going.

“We always want to be able to run the ball,” Roethlisberger said. “It makes you more balanced and helps open up the pass.”