The former New York, Westchester & Boston was an electric railway, with catenary poles running overhead its entire length. A short walk on this trail will confirm this, as there are humongo concrete blocks with steel bolts projecting from the top every few hundred feet. Just south of Ridgeway are the footings for a station.
The railway is only used for the southern half of the trail. North of that it goes through the White Plains composting facility. They don't seem to be using the railbed, but their fence goes around the outside. I see no impediment to doubling the length of the trail northwards. On the south, the railbed has been built upon. Maybe, though, they can lengthen the trail so it meets up with Reynal Crossing. That would open it up as an amenity to all the people who live on the south end.
It's a pretty trail, but should be rerouted to use the railbed, lengthened and eventually paved so that everyone can use it.