[Genma Saotome]

FWIW when Marc Nelson created ScaleRail and used them in a route he was building (IIRC an unfinished B&O Route in WV) he soon discovered the problem of curved track shapes that held > 1 track. His solution was to create a set of congruent curves around the nominal radius of the original track -- two on the inside and two on the outside. These new curves are labeled with the string XCRV. The nominal radius is now thought of as the C track. The four congruent curves became A, B, D, and E. Using these congruent shapes you can lay a multi-track curve up to 5 tracks where all of the shape ends land at the same elevation. The trick is, of course, to add a normal multi-track shape after you place the first of those curves and then to adjust the pitch of each successively placed congruent curve so their ends are perfectly aligned to that multi-track shape. When done, remove the multi-track shape and repeat the exercise with the next set of congruent curves.

Yes, more bother but you do get smooth joints all around.

I will use 2t curves when the pitch is quite low. I never use 3t or 4t curves.