Thanks for the 'memory jog'- been meaning to get this out to you for a while.
I've finally started digitizing some of my copy negative archives, and found this one. Date and location unknown, but it is the 17 as the 17, complete with big square oil headlight and posing crew. The passenger cars look to be from the first series, bought in about 1880. Also note the link-and-pin pilot coupler...
I've been following Ebay for L&HR items for more than six years. If the seller that Greg is referring to is Paladin (at) ime.net, he doesn't appear to have anything earlier than what was on the active roster in the thirties and forties. A good collection, but nothing of the early power.
I don't recall ever having seen this particular shot in print before (with the possible exception of the special railroad centennial edition of the local Warwick newspapers some 44 years ago; I'd have to dig out and look through my copies).