Lots of block and digging unless you are planning to back-fill once track is in place. Just pickup 400 more pounds of Type S mortar so should be able to finish second coat on the north side mountain. It takes about 60 pounds to do a section from base to peak 12 inches wide.Thanks both! I decided to run cinder blocks under my track at 2 foot intervals with ballast in between. I had the block sitting around...