In 2014 I was starting to feel that "seven-year itch" with regard to my current layout (Layout #7). The core issue I had with the layout is that there was no more space to expand it, and that that was all the track I was ever going to lay. At some level, this was disappointing. Also, that layout had been built on cabinets that were only 18" deep, because I built those cabinets when I was in N-scale, where 18" is quite a bit of depth (18" x 2.5 equivalent to 45" in S-scale). The curves on this U-shaped layout were ridiculous.
So, I pondered this for a while in the back of my head, until one day I reached that "ah-ha!" moment. I am going to build X number of modules, based on prototype data, and just work under the assumption that future-Peter would have the space to set up all of these modules into a fully-functional, conventional model railroad. Modules were in my blood, but I was also aware of the fact that they can be quite heavy. Reading about people using foamboard on their layouts, led me to the idea of, "What if I build my modules out of foamboard?". It would be lightweight and easy to move around.
The idea was that I was going to build an experimental module that I would set up in the middle of my room that housed my main layout, and continue to work on both. Since they were to be totally unrelated, this seemed like a good idea and a good strategy (hind-sight: it was!).
The motivation is the same as that of every layout since this moment in 2014, which is to build a true 1:64 replica of portions of the PRR's Chartiers Branch. You can find my prototype research materials about this branch line by clicking on the "PRR Chartiers Branch" button. My decision was to build at least four modules that modeled the Hazel Mine in Canonsburg, Pennsylvania, as my first project.