This roadbed is designed with a more realistic 30-degree slopes found in many  actual  railroad roadbeds.  The scale dimensions are  12" high, 11'-5" across the top and 14'-11" across the bottom.  Actual dimensions are  6.4 mm thick (approx. 1/4"), 7.1 cm across the top (approx. 2-13/16" ), 9.4 cm across the bottom (3-3/4") and 32" long.   Roadbed is sold in 8' bundles.  You receive a bundle of 6 strips, 32" long for each 8' of roadbed ordered.  Roadbed is in halves, so 6 pieces make 96" or 8' of roadbed.  This roadbed is designed so that laying it side to side will yield 3-3/4" track centers.