My team rebuilt 1557 and 1648 a couple of years ago on the C&TS. Both cars had been modified to pipe gons by the D&RGW and then the C&TS and converted them to rider gons at some point. The sills were unmodified though. We measured very carefully and rebuilt the cars exactly the same as they were. Both cars received new end sills, center sills and one car received a new side sill. They are now part of the pipe train. It has been nice to see them go up the mountain a few times now.
The oak end sills of the cars are 6"x10"x7'-10". These end sills stick out 3" on each side of the car wider than the side sills. The top of the end sill is 2" higher than the lengthwise sills to match flush with the top of the decking. The vertical bolt through the end sill is what we have always called "the anti-split bolt" This bolt has been on every one of the dozen or so end sills I have cut and installed. It clamps the ends of the sill and stops it from splitting and spreading. These bolts do not go through the tenons, the truss rods pull the car together to hold it all. The lengthwise sills almost always have them also unless there is a piece of hardware which does the same function. The center sills of most cars, for example, have vertical bolts holding the draft gear in place which do the same thing for the sill.
The fir side sills of the cars are 4"x11"x30'-8" (30'-4" between the end sills). I have seen drawings of this sill stating 12" but both cars were 11" including the chunk if sill still lettered 1648 that my feet are resting on right now. All the tenons on both cars were 2" long with a matching 2" mortise in the end sills. The top of the first tenon is 1-1/2" from the top of the side sill. The tenon is 1 1/2" then there is a 2" space before the top of the next 1-1/2" tenon. There is a 1-1/2" space then a 3" lip that the end sill sits on. This lip is 6" long to match the end sill and is tapered back on the bottom 2".
The center and intermidiate sills are 4"x8" fir. The tenon pattern is the same as the side sills starting at the top. The gons originally had a center sill arrangement that had one 4"x8" sill on top of the other. The bottom sill contained all the draft gear. When the D&RGW rebuilt many of these cars with "economy draft gear" They removed the lower sill to a point behind the bolster and installed a cast bolster and draft gear from scrapped SG cars. This served them well but created a stress point on the upper center sill which has broken the sill in almost every car I have crawled under. The original sill arrangement can still be seen on some of the 9000 series flats converted from gons up in Chama.
This year's project is our 4th drop bottom gon and water car W462. After that we would like to tackle a non-ecomomy draft gear converted flat and a staight hi-side gon. Modeling 12" to the foot every summer for the last 12 years sure has given me a better understanding of the cars I model in HOn3.
