The next step for me was to build the interior of the cab. I plan to install LED lighting, so I wanted to make sure the cab looked about right. The instructions that come with the kit provide a simple sketch that roughly indicates where the parts for the interior are to be placed. However, in October 2010 I visited the Houston Railroad Museum in Houston, Texas. They have several Alco S2 engines on their property. They allow you to wander in and out of the equipment there. I took some photos of the interior of one of them. The significance of that is that an RS-1 is simply an extended version of the S-series of switchers. The interior was probably fairly similar. For reference, I have included some of the photos I took on this page. This first one shows the interior looking from the brakeman's side to the engineer's side.
These are the parts that make up the interior of the Railmaster Hobbies kit. The only thing I forgot to show in the photo was the heater (a tiny rectangular part). The flat, rectangular pieces are 0.040"-thick styrene that are the two floor pieces. The floor has to be cut in two parts, because the center has to be left open for the drive system of the chassis to pass through and swing with the movement of the truck. I temporarily placed the body and the walkway on the chassis and swung the truck to either extreme to see how much clearance was needed in the cab floor. The bottom half of the photo shows the engineer's side and the top half the brakeman's side (the "engine's" front is to the right).
This close-up photos shows the two floor pieces assembled. The figures are just posing; they are not glued in their seats yet. I need to paint those later. By the way, the figures come as part of the kit. Each of the parts have a cylindrical plug under them, so they are easy to install. Each, though, has a different diameter, so I wound up using anything from a #60 to a #54 and a 1/8" drill bit. The parts were glued in place with superglue. By the way, the kit does not come with a brake wheel for the interior. Based on my experience, I would recommend drilling a hole for the mounting pin of the brake wheel into the brake wheel stand before installing it into its location of the interior. I didn't do that, and it took me a bit of extra effort to install the brake wheel later on.
I glued the two interior halves into the cab using superglue only. There is a lip on one cab wall section on each side. I glued the styrene floor on top of that. You have to kind of guess as to how to make it straight. A lip on the opposite wall would have been helpful.
The next day I took the body to the garage and airbrushed Floquil "Primer" to the interior of the cab in preparation for painting the interior.