Gee whiz, the welding instructor of a class I took 30-40 years ago had cut up rails he'd give to students to make anvils out of.
I always found all kinds of good scrap by the railroad tracks back of my little farmstead and made things out of them in my machine shop.
I think I made parts of a steam engine out of some, and I'm almost positive I made a salute cannon out of a huge bolt I found.
I'm sure the television CSI folks could drop a slice of my anvil in a test tube, swirl it around in some acid, inspect the test tube by holding it up to the light and declare, "Yep, this piece of track was made out of a rail rolled by Rolling Machine #762 on January 14th, 1981, and inspected by James F. Perkins, Social Security Number 078-05-1120. Go bring in that dirty thieving rascal Terry, boys."
Terry