Oh, what I do in the interest of scientific discovery. One might think I know something about steam locomotives, but I didn't get to Eddystone until 1954 (and was even in a different department) and that was very near then end of ALL locomotive production. But anyway, here goes: The locomotive was indeed part of a large order for the Pennsylvania R.R. Co. with deliveries during the Summer and Fall of 1926, so the "10" on the plate in question was for October. For the year, 1926, it was #614 for all production to that date, and #191 out of 260 on that particular order. Yes, it was a Mountain type, 4-8-2 with a Pennsy number of #6875. And a raft of "screwy" numbers 14 - 48 1/4 E 191. These are: E indicates that eight wheels are connected as driving wheels. A figure (in this case - 14 - is used to indicate the whole number of wheels under the locomotive, The addition of the fraction - 1/4 - indicates that there is a truck at each end of the locomotive. 191 is the individual designation gives the "class number" for that locomotive in addition to the serial number = 59500. The piston stroke was 30"; weight of engine and tender was 600,300 lb. I would think the RR Museum of Pennsylvania would have a photograph (a copy from original negative) and they were charging a small fee for copies. That would really add to your name plate. Take care, Hank Rentschler.
Henry A. Rentschler