... find so far are in Rod Cameron's post at: http://www.rmweb.co.uk/forum/viewtopic.php?p =190472#p190472 Here I have marked up an extract from Rod's picture: stock_rail_rea.jpg The common REA bullhead A, B, etc. switches are "semi-curved" designs. For an ordinary straight turnout, that means there is a straight portion over the length of the tapered planing (machining) on the switch blade, and only beyond that the rails are curved. Here's a diagram to explain it: set_bend_rea.png Straight turnout: To make a size B curved stock rail for a straight turnout in 4mm/ft scale, do this: 1. Make two marks on the rail with a fine felt-tip pen, 29.3mm apart. 2. At the first mark make the "set", a sharply-defined shallow bend. Sharply-defined means that it is very clearly in one particular place on the rail, a kink, not a curve. Shallow means it is a very slight angle (1 :32 for ...