Not to nitpick, but the DL&W line into Utica was always a branch line; DL&W's mainline ran from the metro New York City area to Scranton, Binghamton, Elmira, Dansville and eventually Buffalo. The primariy DL&W yard though was what is currently NYS&W's yard, requiring virtually all trains called there to venture down the street trackage.
As for the S2s, by the time the NYS&W purchased the DL&W north of Binghamton, I don't think any of these or the RS1s were in service, or if they were they would be kept close to home in Little Ferry (it's possible 1 or 2 RS1s lasted into the mid-1980s). I seem to recall reading that this unit was cosmetically restored and towed places to display in the mid-1980s - seems like it hasn't run in a very long time. I'd have to dig out issues of Jersey Central Lines or early Railpace to confirm dates and just what did still run when the D&O purchased the NYS&W.
I don't believe any of the 539 powered Alcos lasted very long on the DO system, probably the FJ&G units lasted longest. Their early preference was for used RS2/3s and when 251-powered Alcos got cheap and plentiful Rich purchased those as well.