[BAracer]

So the time is approaching when I need to start rebuilding the track.

   

I want to create elevation around the outer loop, rising up from zero to around +100mm. Rather than use the cardboard box lids in the photo, I need some advice on how to properly support the track where it is raised off the baseboard. I was thinking of using a strip of thin flexible hardboard to provide continuous support to the track and avoid sudden changes in gradient. Then I would prop that hardboard up at appropriate points to create the ups and downs I am looking for. 

I had also thought of laying the track on rigid foam insulation board, but I am not sure how easy it would be to carve sloping sections into that material. 

Any advice gratefully received.