Great photo, thanks Larry.
Ms-4 #4876 is the model we keep begging one of the Importers to produce for the market. A USRA Heavy Mikado is sorely missing from the O-gauge hobby except for those handmade by Harry Heike, Joe Scales and a very few others. Southern Railways' mainline freight locomotive for 30 years, 1923--53.
Note the Ps-4s black marker lignts and "stepped" ruinning boards. As Southern's steam power was being upfitted for the WWII years those running boards became straight on most Ps-4s.
Definetely a pair of Aces Larry!