There’s a park trail in Van Cortlandt Park that was once a railroad. It can be reached by walking east through the park from the E 242nd Street stop on the #1 subway line, the last stop. When you reach an overpass, climb onto it: you have reached what is now the Putnam Trail.
The Putnam Branch, or “The Old Put” as it’s called, originally ran from Sedgwick Avenue in the Bronx north to Brewster, New York on the NY Central commuter line, now called the Metro-North. It diverged from the Hudson Line just south of West Kingsbridge Road. Passenger service ended on the line in 1958, and the last fright train rumbled on the now-missing tracks in 1980.
Follow the Putnam Trail just north of that overpass (which is marked with the date it was finished, 1909) and you will arrive at the skeletal remains of the Van Cortlandt station. It throws shadows on the trail reminiscent of train tracks. The Putnam once let passengers out in the middle of the park, which was quite a convenience in the good weather months. Just north of the old station the trail bridges over Van Cortlandt Lake, the largest freshwater lake in the Bronx. The trail continues through the park and north into Yonkers.