I am building a halfstock nickel silver mounted rifle and wanted some materials for inlays I worked for a company associated with the R.R. so I put some nickles on the track, one at a time and let the locomotive run over them.
Thickness runs from .012 to .042 and the largest one is 1.421 long by 1.143 wide with different lengths and widths.
Several things come into play with this, how many locomotives and train cars roll over it how long it stays on the rail before falling off and alloy of the metal will affect the results. I never had a coin to stay on the rail for the whole train, 110 loaded coal cars and three locos, I put a silver quarter on the rail and it squeezed out with the first wheel and went flying of into space. My results points to using this method for inlays and buy sheet silver for the thimbles.