The South County Trailway is a paved bicycle and pedestrian trail that extends from the Bronx line at Van Cortlandt Park to Elmsford (where it continues as the North County Trailway). Both trailways sit on the right-of-way of the long-abandoned Putnam Division of the New York Central Railroad, known affectionately as "The Old Put."
You are at the location of the Lincoln Station, the southernmost station on the Putnam Line within Westchester County. Unfortunately, nothing remains of the physical structure of this station.
Congrats to Behistun and Navigator on the FTF.
The closest access to the trail can be found at the waypoint below. Parking in the area is a bit tricky, especially between April 1 and October 31, when parking north of Alan B. Shepard Place is by permit only. Please pay attention to alternate side parking restrictions as well.