Bruce Smith wrote:
In most cases, I believe that wooden cars were rolled to the side, off the track, before burning. This allowed the trucks, wheels, brakes etc.,, to be salvaged first and without damage from the flames and would have also spared the cross-ties.
Metallurgically, the fire would only have annealed the cast steel and iron parts, not even a bad thing in most cases.
Tony Thompson Editor, Signature Press, Berkeley, CA
Publishers of books on railroad history