PMRR Hazel Mine - Temporary Notes
If you have been following my progress on this sectional layout/diorama, you know that from September, 2014 through February, 2015 I experimented with several modular construction methods using foam board, MDF, and plywood (see my article). Those didn't go so well, but I learned a lot, so it wasn't a waste.

I then built a basic framework out of 3/4" plywood, with a sheet of 1/4" plywood on top of that. I built four of those. That worked well. I wanted to have the Chartiers creek modeled in the diorama, so I decided to build the "ground" level on top of four layers of 3/4" insulation foam board (the only size we can get here in Houston, Texas). That way I could carve the creek out of the foam board.

After I built the first of these modules, I was happy with the direction I was taking, so in October 2015, I decided to take down my first S-scale switching layout, and devote my efforts wholesale to this new direction. After clearing out the room, and setting up the cabinets upon which I build my layouts, I build the other three frameworks in the same manner.

I had noticed that the foam board in the first module was not of even thickness throughout the board. When it was all done, the back of the module measured an S-scale 5" lower than the front of the layout.

January 15, 2017

When I got to the track laying stage of the second module, I noticed the first of several problems. The stack of four layers of foam board didn't match up with the first module's. I bought the exact same brand of boards at the same hardware store, but at a much later date. I guess the boards are not the same thickness from run to run. I compensated for that by making my ties (which I hand-make anyway) to varying thicknesses to match the first module.

Some time later, I decided to start working on laying the rail on the second module. I made painstaking effort to get the rails to line up perfectly with the existing rails of the first module. I started working on the back track (track #1). When I got to track #4, I noticed that the middle section of the ties was raised up quite a bit. I had sealed the ties, so I don't think they expanded during the first round of ballasting I had done.

I cleared off some of the ballast around the bulged area of ties, and then filed down the ties to get the bulge down to where it was even with the rest of the ties. It was about an 8-10 inch section of that track. When I was happy with it, I continued to lay the rails.

I recently painted the rails and tie plates and noticed that once again the bulge had returned. In the photo below, I put a level on the track, over the bulge, and this is how much of a height difference there is to the other side of the 2-foot wide module. My concern is, how much longer is this bulge going to grow? In what way will the other modules' foam boards be different, or behave differently over time? How much effort am I going to have to spend on dealing with base materials that are supposed to be dimensionally-stable, but aren't?
I also noticed that all of the rails of the second module were a significant bit higher up than the matching rail of the first module (see photo below). Again, when I laid the second module's track (left), it was a perfect match to the first's. I ran various equipment over the joint and watched for any movement in the cars, and listened for any serious clicking noises. There were none. So, yes, this could be fixed with some serious filing down of the rails (over several inches of track), but what a lot of work that would be! And, again, how much longer will this track be moving up over time?
With the rail painted, I thought that I could finally complete the top layer of ballast. On the first module, I used a material that, to my eye, looked like coal. These were bags I bought at the arts and crafts store Michaels. They are used for filling the interior of glass containers when planting houseplants or pieces of art in them. They come in a variety of colors, including black and light gray. The individual kernels are just about the right size for average coal clumps in S-scale. They also had a bit of a glean to them. However, I had recently noticed that neither Michaels nor the manufacturer of that material were listing those bags on their web site anymore (the links I had to them stopped working). I want to cover the entire yard scene of the tipple in this coal ballast material, but I had run out of the material. So, I went to my local Michaels store and discovered that those bags were indeed gone. Instead I found the container shown in the photo (and the next photo).
Close-up photo of the kernels (slightly out-of-focus).
When I got home, and I started to apply the ballast, I noticed it was quite a bit darker. The bag material was labeled as a "sand", while this new plastic container has the material labeled as a "stone". I was thinking that maybe the act of applying white glue to the ballast would make it less dark as it dried. Well, as you can see from the photo below, it didn't. There is a significant difference between the two ballast colors. Again, I could fix this by finding some paint color mixture, to try to apply to the ballast (either one) and make them look alike. However, there are two more modules (to the right) that also need this same treatment, so they would also have this dark ballast. I do like the new "ballast"; it is more black, and its kernel sizes are a bit more random. The ballast/scenery company Arizona Rock & Minerals has coal-like material, but it is hard to determine which size would be right for S-scale. Also, they sell theirs for $6 for 7oz of material, while the container I bought at Michaels is $4 for 28oz (and I got a discount on it this time around).
So, I have invested a little over a year into these four modules, but if I intend to keep them and intend to build some really nice scratchbuilt structures on them, I want them to be solid, and something I am happy with. I have therefore decided to start over again. I am going to build the same scene, but this time around I am going to work directly on top of 3/4" plywood, and not use foam board. The individual modules will be heavier, but I am not going to be moving them too often. I will have to do some creative woodworking to still allow the Chartiers creek to be modeled, which means cutting into the framework to dip down about 2-1/2 real-world inches.

One other minor issue I discovered was that my RS-1 engine's fuel tanks hit the plaster-cast tipple foundations on some of the tracks. The American Models FA2 has some issues as well. I placed the foundation blocks as per the prototype design diagrams, but I forgot to compare them against the official S-scale clearance diagrams. So, having to rebuild them will resolve that issue, too.

One final minor issue to note is that I think the foam board is out-gassing. In the Chartiers creek I simply applied acrylic paint over the foam board, and then added a layer of acrylic gloss medium. It all looked nice. However, lately I have seen small groups of embedded bubbles. They are rising up the gloss medium and they are quite noticeable.

I am very happy with the lighting system that I built for the modules. However, the backdrop issue has not been dealt with. I want to figure out how to integrate that (yet have it be easily removable for access) with both the modules and the lighting system. Not having a backdrop is distracting for the photos I take of the layout and post on this web site.

I have a number of freight cars to finish, so while I am working on those, I will be thinking through my plan of attack for these new modules, and share the design diagrams on this web site.