Model Train Scale Rock WallRuss Miller made a scale rock wall for his Garden Railway to hold back the decomposed granite on the far side of his new switching yard so he could hide the real retaining wall underneath. The wall is 1.5 inches high and 72 inches long and about 1 inch thick. It took him 4 days to carefully place select rocked face down into a HDPE Mold that he built from strips of 1" cutting Board screwed together. He held the rock chips together by packing black pigmented Magic Sculp along the backside of the wall; which was the top when it was in the mold. As you can see, the result is a strong, realistic rock wall.