@Phil O @Tony W
Hi Phil, Tony,
The REA drawings go down to 1: 1.5
CLM and show cross timbers and conventional chairs. The timbers are 14" wide to accommodate the angled check-rail chairs. At the centre there are two 12" timbers side-by-side.
Below 1: 1.5 CLM the drawings are silent, but in David Smith's GWR book (p.54) there is a drawing of a GWR 1:1 (45-degrees) short-angle diamond on waybeams (baulk timbers).
The current bottom limit in Templot is 1: 1.5 RAM, 1: 1.65 CLM.
In the next Templot update 228a I have taken the limit down to 1: 0.5
RAM (not 1.05 Phil), but only as far as the geometry is concerned, calculating the crossing angles and locations. It's over to you to sort out the timbering and check rails to create a usable template. Quite often such diamonds are buried in yards and docksides so you don't have to be too fussy.
This is what you get if you make diamond-crossing at intersection
As you can see it falls some way short of being a usable construction template. Over to you.
Above 1: 1.5
Templot adds conventional cross-timbers. But it has never made much of a success of it below about 1: 2.5
because in 00 and EM, etc., the modified gauge and flangeways throw the prototype timbering out of the window -- there isn't enough lead length in which to hide the discrepancies. I'm trying to make some improvements, but finding something which will give good results at all angles for all gauges and scales is tricky. It may have to go to the back of the queue again if I'm to get 228a out in the near future.
At these angles there is a significant difference between RAM and CLM measures. All Templot working is in RAM.