I'm approaching the point where I can start laying down roadbed on the HO scale Chumani Gap RR rebuild. The base is CS foam board. Standard HO roadbed material - cork or foam - is too tall at 5mm to be prototypical for a short line. Has anyone used N scale roadbed for HO track? The N scale 3.5mm high is closer to correct height for the mainline but appears to be too narrow on top, leaving the ends of the ties hanging in the air. Cascade, the former homasote roadbed manufacturer, is out of business and I really don't want to make my own roadbed from sheet homasote.