Freelance writer John Carpenter (a "husky man of 60, with the approximate flexibility of a rusty old tractor") explores some of the abandoned railroads that now have bike paths on them in the Chicago area:
Chicago is teeming with them — rail trails, I mean. Once extolled by the poet Carl Sandburg as the “player with railroads and the nation’s freight handler,” it remains a national railroad hub. That means there are bike paths along existing lines, like the Green Bay Trail beside Metra’s North Line, and trails along the roadbed of long-abandoned lines, like the west suburban Illinois Prairie Path and the city’s Bloomingdale Trail, also known as The 606.
Chicago is also home to a stretch of the Great American Rail Trail, a 6,000-km bike path from coast to coast that passes through northwest Indiana and the south suburbs. Though supported by the national Rails to Trails Conservancy, it is really a network of more than 125 locally backed trails that is still filling out some gaps in the run from Washington, D.C., to the Pacific Ocean west of Seattle. I did a relatively short stretch in Indiana, and it left me wanting to ride more.
The magic of rail trails is rooted in the laws of physics. Massively heavy freight and passenger trains simply cannot handle steep grades up and down. That’s why tracks are built up on bridges and artificial berms in some places, and carved into the land in others, leveling out elevation changes to allow trains to move up and down at a gentle rate.
The result is that riders can easily get into a comfortable cruise. One can maintain a pleasant speed with a steady churn in the higher gears, pushing hard enough to get the heart beating, without the extreme strains of steep uphill slogs. There is also the satisfaction of feeling the miles click away.
He identifies the North Shore trail as "along" a right-of-way, but in fact it covers the old North Shore Line, abandoned in 1964. I used to ride that trail a lot when I was a kid. These days, I sometimes walk a long stretch of it.