MILTON — Three men pound sledgehammers against forged steel, a moment captured in a black-and-white photograph inside Bob Greenly’s office at ACF Industries.

The image is static but imagination allows a vivid recreation of life and labor inside the rail freight car manufacturer in 1937. Cloaked in sweat-worn cotton, stiff blackened aprons tied at their waists, the men strike in successive rhythm to form the dome of a tank car.

“The one thing about ACF cars,” Greenly says, holding the framed photo featuring his great-grandfather, “they’re No. 1 in quality.”

ACF Industries dates to 1899 when American Car and Foundry Company formed with the merger of 13 railcar builders.

The Milton plant churned out hopper cars and tank cars. It continues to build 10,000-gallon versions of the latter as well as propane storage tanks. During World War II, the assembly line produced bomb casings. Its now-defunct sister plant in Berwick built tanks during the global war.

ACF’s legacy predates the end of the 19th century. Its Milton plant was born as a standalone railcar business in 1864 named Milton Car Works, according to Herbert Bell’s “History of Northumberland County.” Its workers built tub-like tanks — two wood stave tanks, about 2,000 gallons each, secured to a flat car. The tanks were used to transport oil during a boom in Northwest Pennsylvania.

Tank cars transitioned shortly to iron cylinders before the turn of the century, Greenly said. American Car and Foundry tank cars were used to transport oil and gasoline, tar, fish oil and molasses.

Greenly explains the cars evolved over the years from being built with rivets to being welded together, the technique still used today. Insulated cars were constructed and eventually coils added to warm deliveries like molasses to ease extraction. The shape was rethought to pitch either end slightly, allowing contents to drain to the middle.

Investor Carl Ichan owns ACF, which is headquartered in St. Charles, Missouri. Greenly recalled an impromptu visit by the billionaire to the Milton plant in the mid-1980s. As Greenly remembers it, Ichan was flying over Pennsylvania and wished to visit his holding. He landed in Williamsport and was driven south to Milton. Greenly said plant workers had two hours notice.

“I remember we had lots of brooms out and did lots of cleaning,” Greenly said.

ACF employed 1,400 at the Milton plant in 1981, Greenly said. About 150 work there in 2019, he said. It’s reflective of how transportation and distribution changed in the U.S.

Chris Nolan started as a welder in Berwick before transitioning to a carpentry job with plant maintenance in Milton. He helps fix the roof and doors, build packing crates and radius boards used to check the curve inside the tanks built on site.

“There’s more females working here,” Nolan said of changes at the plant. “We have some automation that helps get the job done quicker.”