On 5/30/2015 I ran the length of the Old Putnam Rail Trail from Brewster, NY to the bottom of Van Cortlandt Park in the Bronx. I ran this 48.8-mile route solo and unsupported in a time of 6:50:12.
In Putnam County, the trail is known as the Putnam Trailway.
In Westchester County, the trail is known as the North County Trailway and South County Trailway.
In Van Cortlandt Park in the Bronx, it is known as the Putnam Trail.
I began at the trail's start at Putnam Avenue and Route 6 in Brewster. I ended at Broadway and 242nd Street (the southwest corner of Van Cortlandt Park) at the 1 train stop.
Strava record: www.strava.com/activities/315101281
This was a hot day, and I think this time could be easily surpassed on a cooler day.