Dave, going from memory again, the fuselage sections were shipped in halfs, with the fuselage assembly completed in Washington. When I saw the car, the fuselage section was in the container with the windows facing upward. All the metail bending was being done in Wichita and the plant at Renton, IIRC, was doing assembly, wiring, interiors, wings, and landing gear. My dad was an engineer working for a subcontractor that was making the landing gear and he was sent out to Washington to look over a problem they were having with the struts. I was lucky enough to get to tag along with him. It was all pretty impressive. Again, I could be completely wrong but the car looks right to me and the timeframe is exactly correct. I'll be interested to see if anyone can either confirm my memories or see what the car was actually used for.
I can tell you what I think it is. My dad worked on the 747 for Boeing and the fuselage sections were shipped from Wichita to Boeing's main facilty in Washington for final assembly. They used custom made spline flat cars with the container you see for holding the fuselage sections. The inside of the container had steel bracing covered in rubber with hinges to hold the fuselage in place without damage. They then covered it with a large tarp. You can see the tie downs at the bottom of each rib. Mind you, I'm going from memory from seeing one of these cars in Washington when I went out to Boeing on business trip with my dad in 1968 but the picture looks exactly like the car I saw.
