... two central timbers, each with its own slide chair. That's possibly all irrelevant though if you're not modelling GWR or BR(W )! Unfortunately, copyright means I can't share the diagram here. Many thanks for that. I'm aiming for southern 1950s to 1960s. I wonder if that is different. posted: 8 Aug 2020 20:33 from: Martin Wynne Here is the REA/SRC drawing of a 1:12 switch diamond. In this case the middle timber is 14" wide. Low res: 2_081530_450000000.png 2_081531_110000000.png The full hi-resolution scan is at (right-click, Save Link As...): http://templot.com/info/rea_src_12_switch_diamond.png cheers, Martin. posted: 8 Aug 2020 20:40 from: Phil O That looks like a job for Modelu, if someone could lay their hands on the appropriate chairs and get them to Modelu for scanning. Other 3d printers may be available. Cheers Phil. Last edited on 8 Aug 2020 20:41 by Phil O posted: 8 Aug 2020 ...