Roadbed on model railroads is usually used to provide a substrate to fasten track, contribute to sound control, and to provide a way to shape ballast. It also can be used to provide a height difference between main and siding tracks. Prototype tracks aren’t laid at the same grade, and model roadbed can simulate this.
Model roadbed is usually 3′ long cork strips cut on the bias in the center. In theory, one separates the strips, reverses one half, and then has two half-strips to lay on a centerline with a nice shoulder on each side. In practice, I found that I’d get a nice shoulder on one half, and a raggedy straight-edge for the other. I tried two different manufacturers, and had the same results. I don’t know if this problem is endemic to N-scale roadbed, or if all model roadbed suffers this problem. While disappointed that I couldn’t get the results advertised, I had a plan to fix this. Annoying as it was, I figured the problem was easily fixable.
I had the track positioned and joined, but not laid, so I traced the outer edges of the track on the tabletop. The conventional way to lay roadbed is to lay a center line, and then use that as a guide. I thought that I could use the track edges to generate a virtual center line, and as long as the roadbed closely approximated those edges, I’d be good.
Another consideration was that there are areas on the layout that don’t require roadbed: bridges, the coaling trestle, the car pier, and sidings I wanted ‘down in the weeds’. There are some areas that will be embedded in ‘concrete’: to wit, the team track and the sawmill loading area. However, to maintain track continuity the embedded areas still need to be at the nominal grade level, so they got roadbed.
N-scale roadbed is only 1/8″ thick, but for sidings there has to be a gradual transition from the mainline. I used a sanding drum on the motor tool to create the transition, taking care to keep the transition area level. A small orbital sander is the preferred method, but none were available, and I didn’t want to spend $30 on a tool for essentially one-time use. As is, the transitions create a 2% grade, but that’s not unacceptable.
Views of the roadbed installation:
I used Elmers Wood Glue to fasten the roadbed, because it’s what I had around, and it works. My concern is that ballasting may have adverse effects on the roadbed, but I’ll cross that bridge later.
Installing the roadbed went fairly quickly. I let the glue dry for 24 hours before removing the pins.
You can see that the trackwork doesn’t exactly match the roadbed, but that’s a function of the track flopping around without benefit of restraint.
The roadbed portion of the layout was disappointing. Despite my best efforts, the roadbed didn’t exactly line up with the re-installed track. I had to do some cutting and filling, and there are sections that will require attention in the scenery/ballasting phase. There are some areas I would do differently next time, but it’s all part of learning how to build a layout.
I mentioned that I had a plan for fixing the raggedy edges of the roadbed. I figured I could put a sanding drum on the motor tool, and shave away material at at 45-degree angle. This plan worked well. You’ll need a dust mask, but a credible edge can be achieved.
Net up: wiring. The part of the project I’m dreading most.