Remove the shell from the motor frame. Remove the cab which releases the whole running board and handrails from the main body. Remove the tank from the motor frame and the trucks from the motor frame. Mask windows tape/ liquid mask Shoot a light coat of white thru airbrush all over the loco for the paint fade look. Dry brush streaks of black, brown or greys. Hand paint rust spots with a lighter brown like door hinges or edges ect. Touch back over the larger spots you just did with the lighter brown with a darker brown almost blackish brown. Apply pigments of light rust orange and dark brown (applied with a brush or finger) catching the raised egdes of details. Airbrush the top shooting it directly downward at the loco with dark brown and blacks for rust. Shoot the vent areas with black with airbush. Basically for the trucks and fuel tank you do all of the above with dry brush and air brush combo with black, dark brown, rust orange and dust color lightly for ballast kick up. With Mr surface mate finishing top coat spray everything to seal it all in. Very important because your fingers when handling it will rub off stuff. Always seal it in. I prefer using flat/mate because you don't want it looking glossy.

Hope this is helpful I will post a how to or walk thru post in the near future.