The only thing I don't take credit for is the design and concept of this vehicle.
This is a real life concept vehicle designed by Carl Hendrson, Andrew Robinson, and Simon Mattok.
It is being produced under Silvertip Design as an modern road/rail vehicle: http://www.silvertipdesign.com/

But anyway, I did 3D model the whole thing from scratch in 3D Studio Max 7.
The textures I made by pulling parts from a high-res image of the 1/8th scale model on the designers website.
Unfortunatly, this San Andreas vehicle mod does not include the steerable trailer or the ability to drive on railroads like the real bus does.
The driver is positioned in the trailer, and will float in mid air until the truck is connected to the trailer body.
The drive truck is 4 wheel steering, which can be turned on by holding the hand brake just like the monster trucks.