We have copies of the specifications dated Aug. 1915 for the combines and RPO's which still shows wood sills, but unlike the coach specs. mentions steel reinforcing for the sills. The combine and RPO specs. also call for steel reinforcing in the end framing. Since the final products have a good deal more steel than the specs from 1914 and 1915 and have omitted wood sills altogether, I imagine this is a good illustration of the development of passenger car engineering spanning 1910 to 1918. Here is a shot of combine #11 loaded on the a std. ga. flat car at the factory ready to head to Oregon.