Charles, I know you said filing the rail was tough going, but is it actually hardened? If not what plans do you have to harden it? I made an anvil out of a chunk of track, but when I machined the face found it to be "soft" like a tool steel. And every time I've hit something on it I've left marks in the face. I had somebody on here question me about what lead me to believe it was hardened? Not that his question was wrong or upsetting, just gave me food for thought. I've only come across one mention of heat treating such an anvil and that was in The Complete Modern Blacksmith by Weygers. I'm sure there other accounts, I just haven't found them. Your track anvil is very interesting by the way, very cool looking project.