Railroad track makes a pretty mediocre anvil.
People like em for the folksy, old timey do it yourself look, but from
a real blacksmiths viewpoint, they are bassackwards in design.
The idea when using an anvil is to put the maximum force into moving
the metal, with each hammer blow. This is particularly true when you
get old, weak, and sore, like I am. I suppose if you are built like
Popeye or Arnold, it wouldnt matter, but I like to get the most bang
for my buck out of every hammer swing.
So the ideal anvil, in terms of moving metal, is a big square block.
You want absolute maximum mass right under where you are hitting. The
horn was a later addition, after anvils had been used for a thousand or
two years, mostly for shaping horse shoes. Same with the heel, that
little skinny shelf you see hanging off the back of a London pattern
anvil. But for 99% of most blacksmithing, the heel is not needed.
A railroad rail has a tall, skinny, relatively wiggly cross section.
When you hit it, really hit it, the force goes into wiggling the rail,
not moving the hot metal.
A much better design for an anvil is the european style, which is very
blocky and solid in the middle. Short and fat. Or, as the song goes,
"low and slow". An anvil should look like a Rhino, not a Stork.
Check out these anvils- this is what you want it to look like.