Bob Downing

HOMESTEAD, PA.: They are known simply as The Stacks.

The dozen 13-story stacks are impressive, imposing and totally out of place. Sitting in the parking lot of a movie theater, they are a gritty memorial to the now-gone U.S. Steel Corp.s giant Homestead complex.

The red-brick towers are lit at night, a tribute to one of Americas biggest and most important steel mills.

Welcome to Pittsburgh, its steel-making past and the Great Allegheny Passage, one of Americas premier long-distance bike trails.

I pedaled by the 130-foot-high towers on a recent visit to the Three Rivers Heritage Trail that covers 24 miles along Pittsburghs rivers.

I traveled along the south side of the Monongahela River from Pittsburghs Station Square area southeast to Homestead with its historic sites tied to labor history. Homestead is about 8 miles east of downtown Pittsburgh.

Locally, this is known as the South Side section of the Three Rivers Heritage Trail. After a few miles, I was also pedaling on the Great Allegheny Passage (GAP). The Three Rivers trail becomes the Steel Valley Trail extending to the south, also part of the GAP.

The Great Allegheny Passage, nearly 30 years in the making, runs 150 miles from Pittsburgh to Cumberland, Md. The price tag: $480 million in federal, state and local money.

Most of my Pittsburgh pedal was tucked between the river and railroad tracks. It was greener and more shaded than I had expected, a pretty ride with only a short distance on city streets. Eagle watchers were observing a hillside nest along the trail.

I passed bridges over the river and barges on the water. There were city parks and public art, including The Workers, two 20-foot-tall figures made from original girders from the nearby Hot Metal Bridge.

You will also find old giant slag pots used in steel-making and the site of the old Jones and Laughlin steel complex.

Pittsburghs iconic Hot Metal Bridge was built in 1901 to transport molten iron from the blast furnaces on the north side of the Monongahela River to the open hearths on the south side in special rail cars. The bridge carries the GAP from the south to the north side of the river en route to downtown Pittsburgh.

The Stacks at Homestead technically arent stacks at all. They are vents, built to release heat from the red-hot steel ingots or slabs waiting in the mills soaking pits to be reshaped in the 45-inch slab mill by rolling. The ingots came from Open Hearth No. 5 across the river, with 11 furnaces that heated the metal to 2250 degrees.

The Homestead complex was huge. It employed 15,000 workers in World War II and at one time produced one-third of the steel in the United States. Its steel built the Empire State Building, the Oakland Bay Bridge and U.S. Navy battleships.

The 430-acre complex with 450 buildings operated 24 hours a day, seven days a week.

The Homestead Works started in 1881. The mill was purchased five years later by steel magnate Andrew Carnegie. It became part of U.S. Steel that was formed in 1901. It covered three miles of property on both sides of the Monongahela River.

The Homestead complex produced an estimated 200 million tons of steel before it closed in 1986 and it employed 200,000 workers over the years.

The site was sold in 1988 to the Cleveland-based Park Corp. that redeveloped the commercial property, opening in 1999. Office space and residential were later added to what became the $300 million Waterfront project. The Park Corp. later sold its interest in the project.

Not far from The Stacks, trail users will come to another historic site: The Pump House. It is the site of a bloody battle in 1892 between Carnegie aide Henry Clay Frick and the Amalgamated Association of Iron and Steel Workers.

Frick was Carnegies business partner and controlled the coal that Carnegie needed to make steel.

The Carnegie Steel Co., under Fricks management, refused to recognize the union and locked the workers out. The union called a general strike.

On July 6, 300 Pinkerton agents hired by Carnegie Steel attempted to land their barges at the dock by the Pump House to break the strike.

They were met by thousands of angry steel workers and supporters. In the daylong battle, seven workers and three Pinkerton agents were killed. The Pinkertons surrendered to the mob who beat and jeered them as they were forced to run a bloody gantlet into town, where they were taken away by train.

The National Guard was called in and governed the town for 95 days.

The mills reopened with nonunion workers, the strike was called off after four months and unionism in the steel industry ended until the 1930s.

The site at 880 E. Waterfront Drive in neighboring Munhall is on the National Register of Historic Places.

It is home to a short walking tour telling the story of the encounter. The Rivers of Steel National Heritage Area offers a do-it-yourself audio tour at the Pump House for your cell phone or MP3 player. For information, go to touranytime.org.

Across the river sits whats left of the Carrie Furnaces, an interesting site also on the National Register of Historic Places. The Rivers of Steel group offers guided tours of the furnaces that are 13 stories high.

They are rare examples of pre-World War II iron-making technologies, the only blast furnaces from that era that survive in the United States.

The first Carrie furnaces were built in 1884. They were acquired by Carnegie in 1898 and became part of U.S. Steel. The two surviving furnaces were built in 1906 and 1907 and operated until 1978. Today they are rusting hulks from Pittsburghs past.

Rivers of Steel also operates a museum at the Bost Building, 623 E. Eighth St., Homestead, 412-464-4020. The building, an old hotel and a National Historical Landmark, played a key role in the 1892 lockout and strike.

Admission is $3 for adults and $1 for children under 14. Hours: 10 a.m. to 5 p.m. weekdays.

For information on Rivers of Steel, call 412-464-4020 or go to riversofsteel.com. You can also go to http://battleofhomestead.org or call 412-848-3079.

Also along the trail you will find an old gentry crane that was used in the past to unload barges. It is a massive piece of rusting equipment in Homestead.

The Great Allegheny Passage is a personal favorite. I have pedaled sections of the trail but have never done the whole thing.

The route mostly follows old rail lines on a crushed limestone surface. There are tunnels, bridges and viaducts. There are remnants of old industries and small town charms. It is a gentle uphill pedal from Pittsburgh to near Sand Patch, Pa., the highest spot on the trail as it crosses the Allegheny Mountains.

The Great Allegheny Passage offers more long-distance options because it connects with the 184.5 mile Chesapeake & Ohio National Historic Park at Cumberland. That means you could pedal from Pittsburgh to Washington. D.C. 335 miles.

For Pittsburgh tourist information, call 412-281-7711 or go to visitpittsburgh.com.