This is for you 4884 BIGBOY . I have made a bunch of these vehicles for my layout and for selling on Ebay. Here is how I make them. The nicest ones are Boley Crew Cab Stakebeds with Details West Hy-Rail kits, Walthers2005 pg 968. Custom Finishing also make HY-Rail accesories. The scratch built ones are styrene and N Scale wheel sets attached to various Boley and Trident vehicles.Then just add your railroad logos to the doors! I am working on some X-Conrail trucks right now. Here are more Pics.
With Details West
Scratch Built Hy-Rail Tool truck and Dump Truck