Although I don't run these very often on my layout (only as "visiting" locomotives), I have some SD45's and some PA/PB locos, as well as some 6 axle U-boats, that I run on my switching layout that has a maximum curve radius of about 25" with some Atlas No 4 switches in the industrial areas and in staging. these have no problem negotiating those curves. When I get the layout sceniced the curves on the "main" will be at least partially hidden. I mostly run short end-cab switchers and 4 axle road switchers.