Steam engines are mythic beasts -- massive, belching beasts that, in the 1950s, were on their way to becoming extinct. In 1946, steam locomotives moved 78 percent of American rail-freight traffic. By 1951, that number fell to 31, and by 1959, it was all but gone -- less than one percent.

Diesel wasn't the only threat: The rise of the automobile and plane meant the decline of passenger rail more generally. Though modern diesel freight trains still run along much of the N&W, many of the towns have no passenger rail service, shifting the center of town life away from the train station, toward the roads and stores our cars service so well.

But before these great machines totally died out, they were visited by O. Winston Link, one of the greatest railroad photographers of all time, whose work along the N&W is collected in a new book O. Winston Link: Life Along the Line (Abrams), with accompanying text by rail historian Tony Reevy. Link's photographs are recognized for their cinematic lighting, their ability to tell a whole story in a single image, and, often, their nighttime settings, a few examples of which are selected below.

According to Reevy, more than anything, the decline of steam locomotives had a major and direct impact on the workers who ran and maintained these great machines. "The steam engine," he wrote to me, "was a labor-intensive beast. Each locomotive required an engineer and a fireman and steam engines all had to be operated separately; so, two steam engines, a 'double-header,' required two engineers and two firemen." Diesel units, on the other hand, can be joined together and operated by one engineer. Steam firemen were no longer needed.

"What is more," Reevy continued, "steam engines were maintenance intensive, requiring frequent lineside supplies of water and coal, frequent light maintenance by repair employees in specialized facilities ('roundhouses') and fairly frequent heavy repairs in shop facilities." Much of the book showcases these employees, men at work on the trains, but whose jobs disappeared with the steam engines.

Reevy says that beyond the direct effects on labor, the biggest changes in the region were not brought about by the rise of diesel but by the decline of passenger rail with the arrival of the private automobile and jet travel. In perhaps what is Link's most famous photograph (it even made a cameo in a 1998 Simpsons episode, "Dumbbell Indemnity"), all three forms of transportation co-exist, one shot that captures the shifting transit landscape of mid-20th-century America.