I was always fascinated by the Overton combine and passenger cars. They look too short for standard gauge but for narrow gauge they look just right for me (OK the SR&RL passenger cars were longer). MDC Roundhouse have produced these overton cars for years. It is not a big deal to narrow the cars to about 7 1/2 scale feet.
Here you can see (for comparison) a LaBelle standard gauge combine and an original Overton Combine from MDC Roundhouse together with the narrowed combine. See second picture for the necessary cuts (cuts are indicated by red lines).
I replaced the car ends with a styrene sheet and an inserted Grandt Line caboose door (Walthers #300-5063).
Interior: Grandt Line coach seats Walthers #300-5048 (out of production? I am looking for such seats for my passenger car ...)
Roof details: Grandt Line Walthers #300-5043.
Trucks: Precision Scale H0n3 Passenger trucks #H0-31600 (narrowed to H0n30).