Strictly speaking, "Tufnol for dummy spring leaves".
A Google search has thrown up only one reference for pre-forming Tufnol strip for use as (effectively) inert padding between the working steel (or in my case hard temper P/B) leaves for model locomotive springs. The suggestion is that heating the Tufnol to approximately 150 deg. C. should produce the necessary permanent set. Has anyone else had direct experience of this. My material, both P/B and Tufnol, is 1/16" x 5/8" strip. Calculations (formulae from 'Tubal Cain's' book) indicate that a mere 2 bronze leaves would not be over stressed with 40lb per wheel and that more than more than 3 would be likely to be much too stiff.
Experiments with cold bending shows that the Tufnol is remarkably forgiving in that it will revert to almost straight even if after being deformed to a circle of diameter about 12". 12" would seem to be a useful target diameter for my purposes.
While making my search I was reminded that somewhere I have read of soft aluminium being used for the same purpose (dummy spring leaves). Any comments on this will also be gratefully received.