You know how a truly addicted golfer will be mysteriously driven to practice his swing in strange places like station platforms and wedding receptions. He will whip an imaginary club at an imaginary ball, carefully keeping his spine and pelvis in alignment, then will rotate his whole body in a graceful follow-through. It's a little spooky.

The other day I was browsing through the terrific Engineering and Industry Collections at the National Museum of American History when I stumbled upon some of the time-motion studies of Frank and Lillian Gilbreth, the pioneer efficiency experts.

The museum has made large photographic prints of the 2,250 glass plate images the couple created between 1910 and 1924. There are men moving car chassis in production lines; women assembling items from a pile of parts on a table; one-armed men operating typewriters; a man on crutches making umbrellas; men laying brick, mixing cement; a shoe clerk assisting a female customer; a dentist with a patient surrounded by the sort of grim vintage dental apparatus I haven't seen since I was a kid.

Many of the photographs have timer clocks in the background. In some, lights are attached to the people's hands so that their movements describe a pattern in a time exposure. Out of this work came the Gilbreths' great contribution to the Industrial Age: the reduction of wasted motion and fatigue in the factory and office.

And then I found a picture of a golfer who was a subject in one of their studies. He stands in a darkened room, hardly more than a blob himself, but with lights on his head, hands and arms. His golf swing appears as a tangled, incredibly complicated white line in the gloom, a spaghetti dinner of light.

Clearly, Gilbreth was a golf obsessive who just couldn't resist trying out his time-motion techniques in search of the perfect swing. I knew that he and his brilliant wife, Lillian, who later applied efficiency techniques to work in the home, and their many children had been immortalized in the book and film Cheaper by the Dozen. I should have figured he would be a golf nut.

"Actually, today's carpal tunnel research and the field of ergonomics have grown out of their pioneering work in time-motion studies," says Peter Liebhold, a museum specialist who is compiling a history about work. "They felt that all work was made up of a combination of basic motions," he explains. "Using these building blocks of movements, they sought to break jobs down to such an elemental state that they could compare the motions of a golfer with the motions of a drill press operator."

I doubt if anyone ever did any scientific studies of pressers at the factory where I worked back in the 1940s. I had a summer job at the Clarence Williams bicycle-wheel factory in Utica, New York. We put in 40 hours for about $25 a week less withholding. Our pay came in a little brown envelope, in cash. The entire factory operated off a single shaft that ran the length of the rickety, old wooden building. Punch presses, roller presses, paint sprayers, all the machines, were attached to the overhead shaft by leather loops, and when we started up in the morning and after lunch, the shaft had to be put into gear gradually, in little hits, until it got up to speed.

The guy at the next roller to mine — we pressed two-inch-wide steel hoops into bicycle-wheel frames in several stages — was named Yost, a big, red-faced man in suspenders and a high-button undershirt. Every day he would finish his sandwich, tap the crumbs out of his lunch bag and put it over his head — and lean back in his chair and take a nap. That was a good summer.

But they are gone now. Clarence Williams, Yost, the factory, and even the hillside where it perched. It's part of a freeway.

Bill Worthington, a museum specialist in the engineering archives, is surrounded by thousands of files and photographs of work from bygone eras. "We get collections from engineering firms and individual engineers," he said as he led me through a warren of file cabinets and drawers. "We send out the word through engineering societies. After James Forgie, the tunnel engineer for the Pennsylvania Railroad, died, his stuff was left out on the curb with the trash. His life's work. But some passing engineer spotted it and saved it. It's all his drawings and photographs of work on the tunnels into Manhattan around 1910. The best part is his comments written in the margins. Those alone make it really valuable to us."

We looked into the 94 cases that contain the works of Ralph Modjeski and Frank Masters, prominent early 20th-century engineers in Harrisburg, Pennsylvania, whose firm still exists. We saw the files of John Roebling's Sons, the company that made the wire for countless suspension bridges (John Roebling had himself designed the Brooklyn Bridge), and photographs of the old-time steam engines built by Bruno Nordberg of Milwaukee, and the railroad bridges of George Morison. It was Morison who persuaded Theodore Roosevelt to choose Panama for the route of the isthmian canal. At the time, other routes, notably one through Nicaragua, were favored by some.

"We have a diary by an engineer who surveyed that route and drew his own map of it," Worthington added.

Poring over old photographs, tracings and blueprints of bridges from Richmond to Boston, I asked how many of the bridges were still around.

"Oh, they're nearly all gone. They were simply too light. The size of locomotives and rolling stock increased so much in the 1890s that a lot of important bridges were just torn down, even though some of them were quite new. Most were wrought iron, though some were steel. Today they're reinforced concrete and steel."

One charming picture shows a dozen locomotives lined up on the Northern Pacific Railroad bridge in Bismarck, North Dakota. It was a test of load capacity, a rather expensive one it seemed to me, had it failed.

There are tens of thousands of pictures here. The construction of Penn Station in New York and the tunnel that led to it. An insurance map of the Uxbridge cotton mill in Massachusetts, in color. The entire archive of Lockwood Greene Company, 1880 to 1960. The complete drawings of the Burlington Bridge of 1868, which spanned the Mississippi River in Iowa. It's a remarkable document, with the dimensions and every detail, including charts showing the stress on each member, all calculated out, all done by hand.

"And there are photographs of the pile drivers and other equipment used to build it," says Worthington. "This was three years after the Civil War ended. Oh, it's long gone."

One album containing images of every construction along the Baltimore and Ohio line between Baltimore and Philadelphia, circa 1891, was preserved only because an engineer used the backs of the pages for personal pictures. His family pictures have been removed, but the names written under these lost snapshots are still there.

One shot of a stone bridge shows the photographer's handcar waiting on the tracks, the kind two people operated by pumping up and down. Those are gone, too. They used to be a great feature of the comics.

In a cabinet, I saw someone's collection of toy steam engines and miniature waterwheels. In another room, an assistant was smoothing out rolled-up drawings that had come in recently. They were being stored in giant folders and catalogued.

"We spend a huge amount of time organizing this stuff," Worthington said. "We cross-reference everything that we can, to make it easier to find."

Once an engineering firm wanted to see some early design work on the Erie Railroad yards in New Jersey. No one knew where the original pilings were. They could be seen in a venerable set of drawings provided by the collection.

I don't know, maybe some folks will find all this boring. But to me, it's kind of haunting, this glimpse of the real physical appearance of an America that vanished with the passing of the Industrial Age.

When I see these photographs of forgotten bridges and tunnels, when I see the grimy-faced breaker boys sorting coal, and that dentist with his patient, and the lighted golfer, I feel I am looking right into the past. And I realize the past is still here with us, just beneath the surface.

By Michael Kernan