I will have the answer on Saturday - if the excellent Hatton's mail order performs as usual. (I will also have a Queen Mary brakevan in Southern brown too
)
I used to do highway design, but all the formulae were orginally derived from railway work. Pre-computers, we even drew our highway drawings with Railway Curves ! (I still remember the awesome day, when as a young trainee engineer I was finally trusted to borrow the company's mahogany box of brass railway curves from the Chief Draughtsman.... It sounds totally Victorian, but was only 1977)
Hmmm, do you think Parabolic transitions, or cubic-spline? And can Peco flexi track cope with the difference? ............Just give me a big enough hammer, and enough track pins
!