Getting Started with the Model
I have actually modeled a C415 before, twice. About 10 years ago, I purchased an IHC C415 and repainted it Rock Island blue/white to go with what I was modeling back then. I added DCC to it and it ran terribly, so I shelved it for a while. I brought it back out in 2013, replaced the drive and part of the chassis with parts from an Atlas/Kato RS3, added some new details to the shell and replaced the handrails, and added sound. At this time, it was going to be a transfer run from South Omaha as part of my fantasy Omaha Terminal concept.
This only lasted a few months and then I used the drive and decoder to build an Iowa Interstate RS36:
https://forum.mrhmag.com/post/spsf-meadow-sub-iais-rs36-for-south-omaha-transfer-12203521
This idea also did not last long and the RS36 is long gone from my roster.
So I dug through my parts bin, figuring out what I still had to build this C415 for the third time. I still had the shell, although it was not in the best shape, and the chassis was a complete wreck. However, this gave me an opportunity to do an even better job at modeling the chassis. After thinking about it, I settled on two options: I could go with the Atlas/Kato drive and trucks again, or I could use a drive and trucks from a Stewart/Kato F7, swapping the sideframes for a set of AAR-B truck sideframes that I had on hand. While the Stewart/Kato U25B AAR-B truck sideframes are not a pefect size for the real trucks, they are very close and the bearings match those of the C415s in the later years. Plus, the slightly shorter truck length is a little more forgiving under the chassis. I decided to buy a few parts and try things out, then sell what I didn’t need.
Here is a photo of (from top to bottom) the Atlas/Kato RS3 chassis, the Steward/Kato F7 chassis (milled down, from a slug project that I never completed), and a frame from a Proto 2000 FA, which has very similar dimensions to the C415.
First up is the RS3 chassis. What I don’t like this is that the truck mounts are very large. The truck centers (distance between the pins) are 30 feet and would need to be shortened about two feet to get to the 28-foot C415 truck centers.
Second is the Stewart/Kato F7, also with 30 foot truck centers. The disadvantage here is that the frame is very thick and would not complement the sill.
And third is the Proto 2000 FA frame – still a little thick and the very short truck centers, while close to the prototype, would mean that I would have to cut down the driveshafts.
I came up with a fourth option during this process, using a Stewart/Kato U25 frame. The frame easily accepts the Kato parts, has nice coupler mounts, and is fairly easy to cut down to the right truck centers. I decided to compromise here and go with 29-foot truck centers because this works with the driveshafts and should run well. Here is a photo showing the frame in the process of being cut down (I went through about seven Dremel cutting wheels, not as easy as I thought), the old IHC shell, and an Atlas C424 sill.
And here is a photo of the IHC shell, the Stewart/Kato U25B frame cut down to the correct length, and the Atlas C424 sill (also cut down to the correct length).
Backtracking a bit, about the sill and other plastic parts for the chassis: the Alco C424 is perhaps the closest to looking like the C415 – it has fairly accurate steps, pilots, and handrails that match the C415. So I bought a pair of C424 sills from Atlas and cut down the rear of the sill of each one to fit the approximately 49-foot length (pilot-to-pilot) of the C415. I used the March 1985 Railroad Model Craftsman as a guide here, which has an HO-scale diagram with the lengths noted. Using the C424 sill means that the handrails fit perfectly and the stanchions closely match the C415 stanchions. I glued the metal frame to the plastic sill using CA glue and it seems to be a solid chassis.
For the fuel tank and air tanks, I went with some leftover parts that I had from a Bowser C630 (I can’t remember where I got these parts – I may have gotten it from a C630 that I used to own, or perhaps I bought some parts from Bowser). I cut the tanks apart and glued them to the sides of the metal box that houses the Kato drive using CA glue.
Here are some photos that show the chassis in various stages of building. Next up is restoring the IHC shell. I have already done the major work like sanding off the extra fan on top of the long hood, adding the bell and air horn. I just need to add the grab irons again and work on the windows a little.