First glance, from this angle, looked like an NP engine. But the number is wrong...819 would have been a C-11 class 4-4-0. BTW, that's a 4-6-0 in the photo. "2-6-0 819 and train, long ago. Check the cylinders.."
Looks like a compound. Low pressure cylinders outside, high pressure inside the frame, valves serving both. Possibly a balanced or Vauclain compound. Wish I could make out that name.