>The red observation car is Salt Lake And Utah #751. That railroad was short lived.

SL&U: 1912 - 1938, approximately three years shorter than the OA&E/South End passenger service.

>After a number of years of service on the SN main and branch lines

Intermittent use on fan trips (3-4 of them in a 10 year period of time) is "service"? It was used with the NCB 21 in the last train over the M Street Bridge/new port district connection in the early 1960s.

>she was finally repainted back into her original paint scheme at WRM about 10-15 years ago.

Like the Nevada Copper belt, the SL&U was an "Orem road", and the color for Orem roads was red. The NCB 21 was never olive green until BAERA got ahold of it. There were several red schemes for the 751, and the one picked was one of the later ones, the last one being red, with no orange sash, nor orange or black stripes.