Even with a one inch margin, some tracks are perilously close to the edge of the benchwork. My plans call eventually for installing a plexiglass safety shield in these areas.
Once I had a drawing of the benchwork, the next step was to create a full scale version of it on the train room floor. I used blue painter’s tape to mark the edges of the layout. Dimensions were carefully measured, so that the outline would be as accurate as possible. An error of even an inch or two could make it difficult to lay down the rails according to the track plan. This could lead to tighter than projected curves, or yard tracks too close together. Here you can see a section of the benchwork grid with the blue tape marking the edge of the window aisle on the right.
The modules were built using the tape as a guide. In a few cases, where there was sufficient room to expand the track plan, I opted to extend the benchwork beyond the tape boundaries. The 1 x 4 boards were screwed together using #6 x 1 ½ inch flat head screws. Modular sections would be bolted together with carriage bolts.
With a visual representation of the benchwork marked on the floor with tape, it was time to begin cutting lumber and constructing the grid of 1 x 4 boards that would eventually support the foam base, roadbed and track. I chose to construct the benchwork in modules no more than 8 feet in length, to allow for disassembly if that should ever become necessary.
Once the grids were assembled on the floor, the next step was to lift them onto the 2 x 2 legs. Two sides of the benchwork rest against solid walls, so the corner modules were screwed to the walls for maximum support. Sections of benchwork were clamped to 2 x 2 legs cut to a height of 46 inches. The corner sections were fitted to the corner of the room, the legs carefully adjusted to ensure the module was level, and a line was drawn on the wall, using a carpenter’s level to mark the top edge of the grid. The joists were located, and 1 x 4 wooden spacers were screwed to the joists. The benchwork was then adjusted to line up with the spacers, leveled one more time, and the entire module was attached to the spacers with #8 x 2 ½ inch flat head screws.
The rest of the layout was then assembled by building out from the corner. The 2 x 2 legs attached to corners of the benchwork not supported by the wall were fitted with adjustable feet, to allow for leveling once the entire frame was completed.
Once all sections of the benchwork were attached and leveled, I could see the outline of the layout filling the train room. Up to this point, it was still possible to make adjustments, or even add extensions to the plan, if necessary.
Once I was happy with the fit of the track plan, I began to cement slabs of extruded foam cut to the shape of the benchwork. Before this could be done, however, it was necessary to strengthen the wooden grid that supports the entire layout. The entire structure was supported on one side by the wall, and on the other by the 2 x 2 legs screwed to the corners of the grid. A little tug quickly demonstrated that the benchwork was anything but solid and secure. Without bracing, the slightest touch caused the entire structure to move.
Cross-bracing was easy to construct. I cut lengths of 1 x 4 boards to connect the tops and bottoms of adjacent supports, stopping frequently to see if there was any wiggle or sway when I pushed against the benchwork. The entire structure had to be solid enough to eliminate any movement. If not, the slightest bump would cause minor earthquakes and derail nearby trains!
Once the benchwork was solid and secure, it was time to attach the extruded foam to the grid. Foam can be cut with a sharp serrated knife, or with a hot wire. Cutting with a knife will result in small pieces of foam on your hands, your clothes, and the floor. But insulating foam is not nearly as messy to work with as Styrofoam. Foam insulation comes in 4 x 8 and 2 x 8 foot slabs. I found it easier to work with the 2 x 8 size, cutting and shaping the foam to fit the shape of the benchwork. I secured the foam to the wooden grid using Liquid Nails specifically designed for insulation. Where it was necessary to layer the foam for more height, latex caulk is an excellent adhesive.
Although this layout is the fifth incarnation of the Blacklog Valley Railroad, it incorporated several new features: It marked the first time I had designed a model railroad on paper before beginning construction; it was the first time I had fully integrated my own Blacklog Valley with an HOn3 version of the East Broad Top Railroad; and it was the first time I chose to use extruded insulation foam as the base. Extruded foam is an extremely versatile medium for constructing a model railroad, but it does present some unique challenges. In the next installment, I will explore some of the pros and cons of this material.
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