Setrack curves - first rad is
371 mm, 2nd is 438mm third is 505mm, and 4th is 572mm
Half curves in each case are 11.25 degrees, full curves are 22.5
degrees and double curves are 45 degrees. There is also a SPECIAL
curve 859.6mm at 11.5 degrees for use with Y points. Hornby match -
except that AFAIK they do not do 4th radius