Before I developed big plans about my new layout, I wanted to validate some of the main design concepts I intended to use. The first one was, how can I scratch-build track embedded in a street? Moreover, how can I build track in a cobblestone (or Belgian blocks, as the type of stone used in New York City is called) paved street? Using a commercial product was out of question. I know of only two for N scale (Kato and Tomy) and both have limitations.
I had tested scratch-building of track in cobblestone earlier in my Bronx CNJ New Yard Extension but only on a small scale. In that diorama I constructed two track crossings over a cobblestone paved driveway. I used my laser cutter for engraving and cutting the cobblestone texture and grooves for the rails. This time I needed to go bigger. I’d have to embed all street-level tracks in the street. More importantly, the design would also have to support the construction of switches and crossovers. And I planned to have a lot of them!
I decided to use a module that didn’t have too many challenges, both in terms of the track layout but also in terms of the structures placed. The module with the Terminal Warehouse looked like the ideal candidate. It would have two turnouts, one for the stub track ending in the Terminal Warehouse and a second one for a run-around track parallel to the pair of tracks in the Tenth Avenue. Later on, I’d also have to worry about a third turnout that is part of the crossover shared between this module and the adjacent one to the north. And the Terminal Warehouse structure was something I already had started building simply because I loved it.
Benchwork
Before I get into the details about track constructions, a few words about my benchwork. For the modules I use a simple frame of 1×3 structural lumber. The frame is about 16″ by 25″ (40×65 cm) where the shorter side is the width of the module. A 1/4″ plywood sheet made of birchwood that I both glued and fastened with screws covers the frame. I had all the wood cut by the supplier (Midtown Lumber) so the frames all have a uniform and exact size. For the layout, I will fasten those modular frames to a L-girder benchwork. All construction until the very end (or at least to 95% completion) I planned to do on my workbench.
Trackwork Design
First, I had to verify that the tight curve into the Terminal Warehouse was doable. I figured out that with a 7″ radius and a #3.5 turnout I could get a geometry that was still working. It worked for the 40′ freight cars I used for testing and also my Kato NW2 switcher made the turn. I also had to get used to the code 40 rail that I hadn’t used on a larger scale before. After some experimentation and a several wasted pieces of cut and engraved basswood, I found a good formula for my combined street track and roadbed. Here are the specs:
- For the road, I use 3/32″ basswood sheets from Midwest Products.
- Street track is be embedded in grooves. The grooves are about 0.8 mm deep and 1.2 mm wide. ME Code 40 rails are about 1 mm high, so they will not completely disappear in the basswood sheet but stick out about 0.2 mm. This is important for the free rolling of the cars and the locomotive. Also, it’s easier to keep the track clean when the head is slightly above the road. And to the naked eye it still looks as if the rails are completely laid into the street.
- To improve the running quality of the rolling stock I also engraved a 0.5 mm wide and less than 0.5 mm deep groove for the flangeway.
- Designing the grooves in Inkscape is easy:
- Start with the centerline of the track and create a copy for the tracks.
- Turn the centerline into a 9.7 mm wide band by setting the stroke style accordingly.
- Convert the object to a path using the Stroke to Path function.
- Remove the fill by setting it to No paint.
- Set the stroke paint if not set yet.
- Set the stroke style to 1.2 mm; this will result in two parallel lines each 1.2 mm thick and 8.5 mm apart. Note that the code 40 rail head is about 0.6 mm wide, so this creates a gauge that is slightly wider than the 9 mm for N scale (Micro Engineering code 40 track is slightly wider than the NMRA standard of 0.355″ for N scale).
- Convert the object once more to a path using the Stroke to Path function.
- Repeat the process for the flangeways and begin with the same centerline. This time, first convert it into a 8 mm wide band and then set the stroke width to 0.5 mm. This will result in two 0.5 mm wide lines with an outside width of 8.5 mm that fit right in between the two track grooves.
- Use two different colors to control the depth of the engraving for the rail and flangeway grooves (the power/speed settings are specific to the laser cutter used, of course).
- We can take a similar approach for guard rails even though there is no need to cut grooves for them. They will have to be taken into account when cutting the top layer of basswood, though (see below).
- This method will work for both straight and curved track and will result in very precisely cut and engraved track grooves, even for more complicated designs like diamond crossovers. Since the resulting objects are two dimensional with a path for the outline, they can be combined with other objects in unions, intersections, or differences.
- The cobblestone textures are engraved into the same sheet of basswood. We need to mask the cobblestone patterns to avoid excessive depths of grooves when textures are superimposed. Track grooves and road textures should be mutually excluded.
Turnout Design
For the turnouts the design is slightly more complicated.
- For turnouts I use a modified #4 Fast Tracks fixture for code 40 rail. The resulting turnout is more like a #3 or #3.5 switch.
- The shape of the turnout has to be completely cut from the 3/32″ basswood sheet.
- Two layers of basswood replace the cut out piece:
- A bottom layer of 1/16″ thick basswood cut exactly to match the removed piece. That layer has holes cut for all the PC board ties needed for the turnout (as per fixture). This way, stock and point rails sit flush on the basswood base while the soldered PC board ties are hidden in the holes.
- A top layer of 1/32″ basswood with the track and flangeways removed and with the cobblestone texture engraved. This top layer must be glued on top of the lower layer once the turnout is complete and fully tested.
- The resulting friction between moving point rails and the bottom sheet can be neglected as it is minimal. Time will tell if this will still the case in a few years.
- Holes have to be cut for the wire that electrifies the frog and for the actuator of the throw-bar.
- The seams between the cobblestone sheet cut out and the one engraved into the road are less visible when the same pattern is used on the turnouts. Cutting the cobblestone along mortar lines further hides the seams.
It is important to note that the entire road with the cobblestone texture and with pot holes or recesses for sewage caps etc. plus the rail and flangeway grooves are all cut and engraved in one process involving multiple passes. This means that everything has to be included in the vector graphics drawing as adjustments after a cut can usually not be applied without a compromise in the precise location.
Construction
The overall process for the construction of a piece of road with tracks of a size of about 8 by 12 inches begins by first cutting the raw road and track. The second step is to build the complete turnout with long enough stock rails. Next, the road and trackbed must be glued to the plywood surface of the module before gluing the complete turnout with stock rails into the grooves. The last step is then to complete the turnout, and the track and road surfaces.
A word on gluing the rails into the grooves. My first attempt was to use a fast curing two component epoxy glue. That worked okay but to avoid glue touching the cobblestone surface, I had to carefully mask both sides of the grooves. This was a very time consuming process. Also, it was hard to get the proper amount of epoxy. The bond between rail and wood was excellent, thought. Trying a faster (and less messy) way, I then used CA glue which I applied right into the grooves. This method does not require any masking but I had to work fast. The glue I used (Loctite gel) cures quickly.
The CA glue does not bond as well as the epoxy and at least in one case, I had to redo the gluing for a full track. This can be an advantage, though, as it allows correcting mistakes. The epoxy bond is irreversible and an attempt to extract the glued rails from the grooves would result in the destruction of the trackwork if not the entire road and trackbed.
Track and Street Weathering and Painting
Finishing the track and roadbed is straightforward. Once I have glued down the sheet with the road and trackbed onto the module, I usually start weathering the cobblestone. I apply an isopropyl and black India ink mixture over the cobblestone sections. The cobblestone covers about an inch wide area around the track as well as the area between tracks. The roadway of my Tenth Avenue is asphalt covered so I don’t need to weather it yet. However, the side streets are also cobblestone paved (see center photo above) and must be treated the same way. So do have the pot holes and patches where the asphalt is ripped open and the cobblestone layer appears. When the ink has dried, I dry-brush the weathered areas with white acrylic paint until I’m happy with the shade of grey. I’m not covering the coating of the asphalt roadway here but will do this in one of the next blogs.
I’m pretty happy with the street-level track of my first Westside Railroad module. Sure, it is not perfect yet and I will be able to refine and improve the process. Given this was my first attempt, the process and the chosen material and methods worked well. I’m particularly happy with the prototypical appearance of the road and tracks – something that would be hard to achieve with purchased products.