... straight through, one going right (radius 700mm), one going left (radius 700mm). they don't have to both diverge at the same location, they could be offset slightly Do they have to be the same radius? Generally for a tandem that makes things tricky, as it's difficult to stagger the switches far enough to be able to open the second switch, without getting the middle crossing too close to the next crossing. It may be possible with some careful watching of the clearances, something like this perhaps: 2_211949_220000000.png As you can see, the lower check rail on the middle crossing is going to be difficult. A tandem is much easier if the two turnouts can differ. Why is it so important that they are both the same radius? regards, Martin. posted: 22 Oct 2012 17:52 from: julia For clarity it is not critical that they are the same radius. the one diverging to the right has to be 700mm, but the one to the left can diverge by more than 700mm. J posted: ...