I want to talk a bit about model railroad roadbed. This is the material between the tracks and the table or other structural material holding up the track. It simulates the ballast holding the track and ties in place on the real railroad. Usually the roadbed has a bevel on both sides, like the prototype, to promote drainage.
On model railroads, generally you can choose between cork and foam for the roadbed material. Each has their benefits and drawbacks.
Cork Roadbed
Cork roadbed usually comes in 3′ (1m) strips. The strips are precut so you can split it down the middle and end up with two thin strips, each with an angle on one edge. You split it, reverse, and butt the non-angled edges together as shown in the photograph above.
Cork holds nails very well, is easy to cut and work with, and holds curves pretty well. You can spike it down or glue it – your choice. Cork is the traditional material for model train roadbed.
One thing I don’t like about cork is the sharp edge you sometimes get when you split them apart. In the photo above you can see a sharp edge in the immediate foreground. You have to sand or cut this off or it will show up when you ballast the track.
You can buy cork strips individually at your local model train store, or it comes in boxes.
One low cost option is to buy sheet cork from your local home improvement store and cut it! John Longhurst describes how he did it.
Foam Roadbed
Foam roadbed comes in rolls and is quite easy to install – simply unroll and spike or glue down. I prefer glue as it doesn’t hold spikes very well.
Foam is very easy to lay and is uniform and looks good once ballasted.
I find foam is harder to shape to curves and this may be a drawback, especially with sharper curves.
Typically you buy a box of foam roadbed with 24′ (8m) in a box.
Elevation
If you look at the prototype photo above, showing main line (left), siding (middle) and spur (right) track, you can see one important detail. The main line track is higher than the siding or spur tracks. This reflects greater amounts of ballast and general better construction of the main line track, which is intended for the highest speeds. Sometimes a lightly used industrial spur has little to no ballast at all.
You can simulate this on your model railroad using a few techniques. What I have done on my layout is to lay main line and siding track on HO scale roadbed, and industrial spurs on N scale roadbed.
The track in the foreground above is laid on N scale cork roadbed, while the track in the background is on HO scale roadbed. It makes a subtle difference in the elevation.
Note that for cork roadbeds, you’ll need 3 strips of the N scale roadbed to be wide enough for HO scale track.
In order to get main lines to be slightly elevated above sidings, I used cardboard shims under the roadbed. You can see the shims in some of the photos above. I simply cut soda cracker boxes into strips and glued them to the table first before laying the roadbed on top. I love soup so I always have empty cracker boxes.
The Winner?
So… cork or foam?
For me there is no winner. I always used cork in previous layouts, and I have laid cork for the CN track in my current layout. I decided to try foam out for the CP track to see how it works out, and so far I prefer installing the foam over cork. They both cost about the same. Time will tell which works best but I have a feeling it doesn’t matter a whole lot.
What’s your experience been?