This is a pretty good resource for Fast Mail consists:
Only the green and gold ATSF Express boxcars were used on the Fast Mail. The red oxide cars were strictly in the freight pool. The Pecos River car is a good representation (I've got a couple). Otherwise any mail/express/baggage/RPO is fine in the consist. The Fast Mail frequently ran with eastern road (PRR, NYC, & B&O) cars, both boxcars and baggage cars, in the consist. Last car was always an ATSF "rider car", which was a heavyweight combine with markers on the rear.
The Fast Mail I run on my layout usually consists of:
Pecos River ATSF Express boxcar
Pecos River ATSF Express boxcar
Weaver ATSF Express boxcar
MTH ATSF Express refrigerator
Atlas ATSF baggage car
Atlas ATSF RPO
Atlas ATSF baggage car
Atlas ATSF combine
I usually run the Fast Mail with one of my ATSF 3460 class Hudsons, but any ATSF Hudson, Northern, Passenger F3/F7, or PA is fine. E3/E6 and DL109s could also be used, but that would be before they were bumped from the transcon pool by the arrival of F units and PAs in the late 40s.
