PRR Chartiers Branch: Hazel Mine - Layout Design
Almost all model railroaders want to have plenty of space to model a chosen area without any compromises. I am no different. Of course, we all have our constraints. These are any combination of time to devote to the hobby, space in which to set up our layout, money to spend on a pastime, and to some extent creativity to help come up with unique solutions to deal with these constraints.
What is it that I really want out of this hobby? When I returned to the hobby in 1999, I wanted to try out the hobby, to see if I still liked it. I concluded that I did, very much so to the exclusion of my other hobbies (woodworking, electronics, audio/video, owning classic cars). Next, I was convinced that I wanted to have continuous-running. This was because the modeling media says that you must, due to entertaining visitors and having operating sessions. About 30 minutes after I got the trains running on such a layout, I got bored! On top of that, I have had about a dozen visitors to all my layouts since 1999, so the idea of making your layout so that it meets some arbitrary objectives for entertaining others is just silly. It is your layout, so build it to your standards. Especially if you are a "lone-wolf" modeler, like I am. When I got to operate local area layouts a few times per year, I discovered that I really enjoyed switching duties (moving cars around onto different tracks). After several false starts in N-scale, I finally built my first true switching layout in S-scale, and I really enjoyed it for 7 years. The model railroading media also tells you that you cannot model a scale version of the real thing. "Selective compression", it is called, and we must all abide by that. This frustrated me, because my real interest has always been to make a scale model of the real thing. Additionally, I also started examining where I actually spent most of my time when I am involved in the hobby, and which of those activities did I seem to enjoy the most. It turned out that operations was a very small fraction of it. What I actually enjoyed doing the most was "building".
Do What You Love!
What I really enjoy doing is taking some basic raw materials (wood and styrene plastic, mostly) and shaping and forming them into models that can be displayed, and in the case of locomotives and cars, be run and operated. I enjoy building the layout's framework out of wood, building the track out of its raw components (ties, tie plates, rail), building the equipment (freight cars so far, but passenger cars, and eventually steam locomotives will come in the future), building structures, and creating and super-detailing scenery. I have always enjoyed those beautiful museum displays, whether animated or not. The craftsmanship that goes into building something believable has always been fascinating to me. So, if those are the activities that I enjoy doing and (most of the time) find relaxing, then that is what I should do within this hobby. The end result of this effort is a 3D representation of what I had in my head.
Modular Design
Since about the year 2000, I have been involved in modular railroading. I was involved in a modular N-scale club for a couple of years, and since 2008 I have been involved in the local modular S-scale club. Modules are an effective way to transport and set up a relatively large layout fairly quickly. Of course, these layouts are used to entertain the show's visitors. However, the idea can also work effectively in a private, home layout. A modular (conforms to some common standard) or sectional (arbitrary shapes and sizes) layout is easy to move (either within the home, or to another house), and could potentially be taken to local train shows or be sold off. A more traditional layout that is built like a fortress inside of a room or basement is all but destined for a landfill when it is no longer wanted. I will be using the words "modular" or "modules" throughout, despite the fact that my diorama will not conform to any modular standard; it just rolls off the tongue easier than sectional.
Back to the Hazel Mine
So, with that background in mind, I decided that I wanted to model a true 1:64 scale replica of the Canonsburg Hazel Mine and its immediate surroundings. I want to do this in a modular fashion, so that I can take it apart and take it with me in case of a move. I also want this to be "permanent", meaning, I am tired of throwing layouts away. The ultimate goal, given the removal of the above-mentioned constraints, is to build a scaled-down version of the entire 23-mile PRR Chartiers Branch line in a dedicated building some time in the future (dream big!). So, the Hazel Mine layout is going to be a diorama that would be integrated into this larger layout down the road.

February 04, 2017

Area Schematic
The diagram below is from a Sanborn insurance map dated November 1913. The space of the entire diagram scales out to be 4' by 8' in S-scale (1:64). I purposely kept the slightly rotated angle of the tipple on the right, such that most of the track work does not parallel the front edge of the layout (which is the top edge in this diagram). Yet, the orientation allows for the complete capture of all the main structures around the tipple, a good chunk of the Chartiers creek in the back of the layout, and even a bit of the Fort Pitt Bridge Works buildings (the gray rectangles in the lower-left corner). The track is still toward the front of the layout (for easy reach), and most all of the buildings will completely fit within the modeled space, including the mine entrance (in the lower-right corner of the diagram). Also shown in the diagram are two vertical orange lines. These represent the dividing lines of the individual modules that I am going to build. These were placed so as to avoid cutting structures in half. The other constraint is that the modules cannot be more than a total of 29" tall, for them to still fit through a regular interior house door. However, my estimate is that none of the structures will be that tall (as a matter of fact, my design calls for the removable backdrop to be 22 inches tall).

April 02, 2017

Here is the same diagram, rotated such that it is oriented in the normal viewing angle. The front of the layout is along the bottom edge of this diagram. I actually like this arrangement better than the previous attempt I made at modeling this area, because the track isn't right at the front of the layout. The foreground structures will hide some of the locomotives and cars on the tracks, which will make the whole scene feel bigger than it really is.

March 10, 2017

Design Diagrams
This time I want to build a fairly complete CAD drawing of the entire project, so that I can think through all the steps to making this new layout/diorama, and so that I can share with you what is in my head. While "forcing" myself to do this, I have already had some additional thoughts that helped me figure out how to better build this diorama, so spending time doing this CAD work is well worth it. This first screen capture is of the core framework of the three modules that make up the diorama. The modules are all 48" (122cm) deep. The one on the left is 36" (91cm) wide, the middle one is 25.5" (65cm) wide, and the right one is 34.5" (88cm) wide. The boards are 6" (15-1/4cm) tall. The butt-joints will be glued together using biscuits.

March 27, 2017

In the next diagram, I placed some corner reinforcement blocks in the four corners of each of the modules. I may not use these in the actual construction, because at first I was going to make this a very open-frame construction, but I have since then thought about just placing a 4'x8' sheet of 3/4" plywood on top of the frame. My original idea was to try to save some money and build it out of one sheet of 4'x'8' plywood, but there is just no way to do that, so since I have to buy two sheets anyway, I might as well use both of them.

Since it is relatively easy to do in the CAD drawing, I went ahead and added the three pieces of 1/8" Masonite hardboard to the diagram, to show the effect of installing the backdrops. These will be bolted to the frame, so that they are removable. I did want to have one long backdrop in the back to make it appear without seams. The backdrops are 24 inches tall, with 18 inches visible. The backdrops will need to be painted away from the framework, because it will be impossible to reach them otherwise.

April 02, 2017

Using the above-mentioned Sanborn diagram, I copied the x-y coordinates to the CAD drawing for the Chartiers creek placement. This represents the ground-level width and direction of the creek. I used a spreadsheet to calculate the coordinates and saved those, so that all I have to do is mark those locations on the plywood sheet and trace them out with a jigsaw. The idea is to cut the creek out of the single 4'x8' sheet as one piece. Once so cut, I will then cut them to match the dividing lines of the three modules. I will only be modeling the top water surface of the creek (based on what I learned from my previous attempt at modeling it), and so this piece needs to be moved down about 2 inches (about 10 scale feet, which is what locals have mentioned is the normal level of the creek) from the ground surface. I will then be able to model the creek's sloped banks from that dropped-down surface to the ground-level surface with my usual scenery base modeling techniques. The water surface will be painted a dark color, and one or more layers of Enviro-tex epoxy will be applied to this surface to represent the water. This will be one of the first things I'll do after building the basic framework, since the creek is at the back of the diorama, and some structures and trees will be overhanging the creek, making subsequent work on the creek harder. Also, once I have the backdrop installed, working on the creek will not be impossible, but more time-consuming due to having to remove the backdrops first.
The track layout of Sanborn insurance maps should always be taken with a grain of salt. However, their overall placement is probably close enough for an initial CAD drawing. The gray space in the diagram below represents the space taken up by the five tracks of the coal mine yard. I plan on making a dedicated track-planning CAD drawing in the near future, because I need to know where the turnouts are. I need to know the approximate space taken up in the diorama for the track area, because I plan on using ceiling tiles as the roadbed for the track. Due to the height increase (from above the plywood base), the structures need to be raised up as well, so I plan on putting them on ceiling tiles as well. I used ceiling tiles on my previous S-scale switching layout and I was happy with their sound absorption and their stability over the 7 years I had that layout (they do need to be thoroughly painted).

April 09, 2017

The design has evolved a bit more. Based on the idea that both track and track-dependent structures need to be built on top of the 1/2" ceiling tile, I decided to just cover the entire 3/4" plywood base with ceiling tile. So, that is what you are seeing in the diagram below: the vertical frame, the 3/4" plywood base, and the 1/2" ceiling tile. The track and structures will sit on top of this, and the creek will be cut out from all of them, and set at about 2 inches below the top of the ceiling tile.

April 12, 2017

With the recent design change of just using a full sheet of 3/4" plywood as the frame top, and applying 1/2" ceiling tile as the sub-roadbed, it became obvious that the front of the layout would now show the layered-cake look, which I don't like. So, in this design update, the front frame members have been raised by 1-1/4" to 7-1/4", so that the layers are no longer visible. On the sides and the rear it doesn't matter, because the backdrops will hide that.
However, to provide support for the top layers, which have now been shrunk back 3/4" and are no longer supported on the front, an extra board is necessary behind the front frame board. These don't have to be full height, so I made them 4 inches tall. Then thinking about the four-foot depth of the frame, I decided that it might be prudent to put a 4-inch tall brace in the middle as well. This provides support for the "ground" layer of plywood, and it makes sure that the long side panels stay square to the front and back (since they could potentially bow out or in). Both of these are shown in black outline in the next diagram. All of these changes will still allow me to cut these parts out of a single sheet of plywood.
Getting into new territory for me in the CAD program, I cut out the modules of the framework pieces on top of which the river piece is going to be placed. When I actually cut out the river top piece with a jigsaw, I will be able to trace it exactly on top of the framework pieces. The depth of the cut needs to be 2 inches minus whatever the thickness of the ceiling tile is. The river pieces will be attached to the framework with glue only to keep their top surface as flat and smooth as possible.

July 23, 2017

I have updated the CAD design to match what I have actually done to the backdrop panels. I have cut a groove in the top edges of the modules, and have sat the panel into that. Where the creek "touches" the backpanels, the panels go down to the level of the creek. This is not shown in the CAD drawing, because I haven't figured out how to do that yet in the software application.
However, the next objective is to design the LED lighting framework that sits on top of the backdrop panels. The idea is that between the grooves in the modules' edges and the grooves in the LED lighting frame on the top, the backdrop panels will not move, and will stay aligned. And, yet, the whole system is relatively easily taken apart. This diagram shows the basic framework. It is planned on being made out of 1"x2" poplar, but it may have to be 1"x3", if the poplar available at the time is not straight enough. Near the bottom edges a groove will be cut around each section, so that a clear plastic sheet can be slid in that diffuses the LED lights above it. The sheets will be slid in from the back, so the back board may need to be a bit thinner vertically. The overhead frame sticks out about 6 inches outside the front of the layout. This is so that light can be provided to the very front edge of the layout. That was something I learned in the last layout I built. The entire framework will be painted white, especially on the interior.
The green lattice work on the top of the framework represents the strips of LED lights. There will be 9 of them, spaced 6" apart. They will be glued to 8-foot lengths of aluminum framing (used for making custom window screens). That provides a strong, yet lightweight system. I have tested this method for more than a year now and it works great. The aluminum frame actually aids in dissipating the heat generated by the LEDs. They will be screwed to the top of the wood frame.
Here's a top-down view of the LED light strips (green) mounted on top of the wooden framework (red). I may put a 4'x8' sheet of Masonite hardboard on top of this to contain the light (painting it white). Or, I may leave it open so that light that escapes helps light up the rest of the room. If the aluminum framing pieces for the LED light strips prove to be too unsightly, I may put a thin strip of Masonite hardboard around the front and side edges of the wooden framework, to dress it up a bit.
And, here is a 3D-shaded view of the entire modular setup. Tear-down would involve, popping off the lighting framework, carried with the front edge down, so that the clear plastic diffuser panels don't fall out. The three backdrop panels pop out next. Then the bolts holding the three modules together can be removed. The three modules can then be moved.