I've had a side-interest in German Z gauge for a while, but only built a plain track "pizza" so far because the Märklin points look so awful. However I've been cooking up a plan to build a small shelf layout representing a station on the Höllentalbahn (Black Forest) so I decided to try putting together some finer track. This layout built by Will Vale has been an inspiration - not least in realising you can thread code 40 flat bottom rail into Märklin flextrack sleeper bases.
This is a B6 curved turnout I printed (rather haphazardly) from Templot, constructed with 2mm Scale Association code 40 flatbottom rail and "2mm narrow gauge" sleepers and turnout sleeper strip. The aim was to build something that would look a lot better than Märklin turnouts (curved example in the picture) but still work with out of the box locos and stock. I settled on a flangeway gap of 0.8mm, rather than the 1mm of the Märklin points - still pretty generous - and conveniently the thickness of the PCB sleeper strip, so I could use that as a spacer. I did buy some 2mm Association roller gauges for 6.5mm gauge, but they are designed for code 30 rail, not code 40 - so didn't fit. In the end I made do with a square of scrap etch cut to 6.5mm as a gauge, along with some heinous abuse of some digital callipers.
I found that while a bogie wagon or coach went through perfectly before I added the check rail, a 4 wheeler (longish wheelbase) tended to derail on the diverging route. When I build points in 2mm I usually judge a wagon running through reliably without checkrails in place as a sign of success. When I added the checkrail for the diverging route, the wagon seemed to run much more reliably, and still smoothly. Tightening up the flangeway gap on this checkrail slightly (to 0.7mm) has resulted in what looks like flawless running.
Is it inevitable that a turnout built for "pizza cutter" type wheelsets (which have lots of horizontal slop - they run in central "bearings", not pin points) will actually need the checkrail to function? Or is there a problem with my crossing?