Army 611, that is, at Ft. Eustis, Va.:http://saulnadler.railfan.net/display.cgi?USArmy611_part1.jpgCloseup of the Caprotti valve gear.The 611 (then the 2628) operated briefly on the Maryland & Pennsylvania RR to test the new valve gear in the early 1950s.

Nice find, Bob!Are Tennessee Valley RR (ex Army) 2-8-0's 610 and 611 consecutively numbered because they were both produced around the same time (early '50's, LATE in the steam game, by Baldwin-Lima-Hamilton if I remember correctly)? Or was numbering for the US Army similar to the Pennsy's, with open numbers used at random?Either way, that poppet valve gear is fascinating. (EDIT - I said Caprotti the first time, oops!)

Caprotti? That ain't no I-talian engine! That's Franklin "Type B" rotary cam (RC) poppet valve gear.Nice photo though- thanks Bob.

Right, it is Franklin, not Caprotti valve gear. I believe the 611 is of WWII vintage, while the 610 is a Korean War era locomotive, of about 1952, similar, but not an exact copy of an S160.