Skidway of more than 3,000 logs above railroad tracks, somewhere in Pennsylvania, circa 1900.

Credit: Courtesy of the Pennsylvania State Archives

In the late 1800s geared engines built by specialized locomotive builders revolutionized the Pennsylvania timber industry by giving logging companies access to vast stands of previously inaccessible old-growth forests. After felling the trees, loggers would drag the logs to a common area to await transport to sawmills.