This is an idea that's been batted around every now and again, with nothing much more than talk involved. Nice idea, but I'd be hard-pressed to make anything near a viable business case for it.
The nearest active rail to Stewart is the northern end of the former Erie Newburgh Shortcut (Newburgh Jct. to Newburgh waterfront, with a north-facing connection to the River Line). That line stub-ends at Vails Gate Manufacturing, adjacent to the point where NY 94 crosses under the NY Thruway in Vails Gate. The portion of the branch south of there, to Newburgh Junction on the Graham Line was abandoned in 1954, if I recall correctly. Not exactly useful.
The O&W's Cornwall Extension at Little Britain was actually the closest rail ever got to the Airport terminal -- just outside the current periphery of the Airport, proper near NY Route 207, and more than a mile and a half from the Terminal building. Of course, that went away in 1957.
Neither of these routes are useful, even if they were still available. Extending east about 8 miles from the Maybrook Yard site might be feasible, as the airport's Buffer Zone abuts the former rail yards. However, the intervening area covers lots of wetlands, plus one would have to consider the absurdity of a "go west to come east" looping of a connection all the way to Campbell Hall for a connection to the Graham Line.
Aside from the issue of establishing a right-of way through a rapidly-developing area, the big issue is, frankly, "why?"
I use Stewart frequently for business travel. I like the notion of arriving for my flight a half-hour early, getting through TSA checks in about 10 minutes (on a bad day) and at 10 miles from my house, it is a heck of a lot easier than going to Newark or Albany.
Having said that, the retrenchment of airlines from Stewart has been, well precipitous in the last year:
--United Express discontinued service last year.
--Southeast Airlines went belly-up.
--Delta discontinued service at the end of August.
--Independence Air cut back to three roundtrips per day to Washington, and is pulling out altogether by November.
-- ...and we won't even go into the Pan-Am fiasco (Guilford's Boston-Maine Airways) which ended after three flights, union busting, and the lifting of their flight certification!
All that's left after that, as of now?
Three roundtrips to Chicago on American/American Eagle
Two round trips daily to Detroit on Northwest
Seven round-trips by USAir/Piedmont Airlines to Philadelphia (prop-job)
Charter airline Allegiant Air is to start discount service to Florida (essentially replacing Southeast Air) at the end of October.
Annual passenger counts at Stewart, for periods ending August 1:
http://www.recordonline.com/archive/200 ... ithers.htm
There is a booming cargo business for FedEx and DHL, but that's not likely to be feeding rail traffic anytime soon.
Local bus company Leprechaun Lines runs a bus connection to the Beacon train station on the Hudson Line, for all of $1.50 fare each way.
Almost all of the ridership is between the Route 17K Park-and-Ride and the train. Most passengers I've ever seen on the 17K-to-Stewart section? 3 -- and I was one of them!
SAFETEA-LU has money for a rail link, according to a press release from the Airport and Congresswoman Su Kelly:
I'll be REALLY interested to see how they propose to do it...and what route they recommend.