N scale (1:160) Buda 6-bolt wheel stops - 32 per print. Sized for Atlas code 80 rail; use a tiny drop of white glue or ACC to fix them to smaller rail. Each wheel stop measures 5.5mm long, 4.8mm tall and 1.5mm wide. Based on a CN prototype. Price is $0.60 per wheel stop. A precision sprue cutter like the Intermountain BB-1015, Micro-Mark #82393 or UMM-USA GMT01 is the best tool to cut the parts from the support framework. http://umm-usa.com/onlinestore/product_info.php?cPath=21_28&products_id=3749 Cleaning, sprue removal and installation instructions are in the Instructions section of the Shapeways Forum: http://www.shapeways.com/forum/index.php?t=msg&th=12233&start=0&