As someone who has had the opportunity to actually look at these up close I noticed that the wheels are 0.1 or 0. 2 inches wider than the track in game, it is also equal to or larger than an EMD E unit, also from my research most F units except for FT's, F2's and early F3's only had two porthole windows on each side while the FT's had four porthole windows on each side, F2's and early f3's both had three porthole windows on each side almost all EMD E units had four porthole windows on each side. Also according to the research I did ditch lights are not accurate for both the EMD F Units and E Units before 1990's there may have been exceptions but it has not been well documented, also the boxes on top were discontinued on the F3 Phase two model locomotives and are non existent on the EMD E units. Just from looking at the model I would say it is closer to the E unit than an F unit as you can only tell the two apart from the number of axles the placement of the door to the engine compartment, the number and the placement of porthole windows on the side as well as the length of the locomotive. I can not find any record of Western Pacific ever having diesels numbered in the four hundreds except for subsidiary company Sacramento Northern and those were yard switching diesel locomotives or electric locomotives. other than the thins that I have pointed out, I really like the mod and the textures are 100% accurate.