I've had good luck making my transitional ramps out of plain masking tape. If my transition will be 12 inches long start with a 12 inch long piece of masking tape laid down on the layout where you want the transition to start. The nest piece of masking tape will be 11 inches long, and the next 10 inches long, etc.. all laid one on top of the other. The result is a very smooth transition with no mess. If you find you need more pieces of tape to equal the height of your roadbed, just rip the old stuff up and start again only using 1/2 inch changes in tape length. You can make a transition in about 10 minutes. If you need to make a transition on a curve you can cut your tape lengthwise just like roadbed and lay along either side of the track centerline. Brian.
fwiw Celluclay is a wonderful product that comes in quite handy for such purposes, along with other scenery tasks. http://www.amazon.com/s/?ie=UTF8&ke...vptwo=&hvqmt=b&hvdev=c&ref=pd_sl_4yattkmzu3_b It works best mixed with "wet" water and has a long curing time wherein one can make very micro-changes to thickness / shape / texture. Helping the curing process over night with a fan moving air across is reaps great results. It is available at many LHS and the craft stores whose names we all know. just sharing for whomever might be helped with this information kindest regards Gary
