PRR Steam, Look for an undecorated GGD coach with 3 axle trucks. Highball Graphics has O scale decal sets.
The undecorated MTH car may work. Not sure if letterboard is wide enough on these cars to accommodate the Rutland lettering. There are multiple decals in the set that can be placed below the windows. Not sure where these molds are going to end up. This is the set that will sell. Repainted and decaled with Highball Graphics.