... but is to your chosen standards (I think). Attachment: attach_1730_2336_roys_slip_2014_01 _28_1403_06.box 222 posted: 28 Jan 2014 14:21 from: roythebus Thanks, I'll try that on the layout later. posted: 28 Jan 2014 21:51 from: Martin Wynne Hi Roy, I have looked a bit closer at this. In 4mm scale, with the 1:7 slip switches pegged as intended on MCP and TCP of the half-diamond, there is 3.6mm between the switch tips, measured with the ruler tool: 2_281656_270000000.png 2_281636_260000000.png With one switch blade opened by 1.75mm at the tip, and allowing .25mm for the tip thickness, that still leaves a clear space of 1.6mm on the other rail for the wheel flange. Which should be more than adequate for all wheels. By reducing the opening to say 1.5mm (still a bit overscale) it would be possible to have both switches open at the same time -- e.g. when operated by hand levers in a yard. And also in some GWR interlockings. Admittedly it needs some careful fitting of ...