I am planning to add a narrow gauge to my HO layout, using HOn3. Does anyone have any ideas on how to build a crossing of the two different gauges of track?
The same way as one would build a crossing of two standard guage lines. One track just happens to be three foot guage.
Have fun
PS The above two sites have some info on handlaying track.
There would be no difference from building a normal crossing. The first thing to do would be to “convert” to the same weight of rail (or in model terms code of rail). I believe HOn3 is typically code 55 or 70. So the standard gauge would have to drop to 70 or the narrow gauge would have to run on something larger (code 80 or 100) for a while to go through the crossing.
There was a company that use to make custom turnouts and track work. In their MR advertisement they used a dual gauge crossing through a dual gauge turnout. It looked way cool, but I couldn’t imagine any practical use for trackage that complicated.