Realistic CSX locomotives

I need two fully-rigged, realistic CSX trains that will run through an industrial-area map in my Roblox game. Each train should capture genuine CSX proportions, textures, and markings so players instantly recognise them as modern U.S. freight units. Because these will operate in a gritty industrial setting, weathered materials, subtle grime, and authentic lighting bake are important—think practical railroad, not showroom polish.

Functionally, both trains must behave as working freight units: smooth forward-and-reverse movement controlled by the default Roblox vehicle seat, sensible acceleration and braking curves, and a simple cargo workflow (open-top cars or boxcars that can visually load/unload when a script toggles them). Please script the movement and loading logic in clean, commented Lua so I can tweak speeds and triggers later.

Deliverables (each as separate .rbxm models):
• Locomotive A is a ac4400cw with yn2 and yn3 csx paint schemes
• Locomotive B is a sd40-2 with yn2 and yn3 csx paint schemes
Both must arrive properly welded, rigged, and ready to drop into Studio with no missing textures or dependencies.

I will test in-game to confirm: collision boxes align, couplers attach, sounds trigger correctly, and the loading animation syncs with the scripted state change. Once those checks pass, the milestone is complete.