My father worked for the railroad and it was common for anyone who wanted one to have an anvil made from old railroad track. He always had one, and he had one made for me also about 45 years ago. I've had it ever since and moved it from home to home.
I've always used it for anything I needed to have a good base to beat on, but it seems as I get older the anvil gets more finesse use, and not just the heavy beating. I shaped many of the parts on my project using it, and although it's not a "real" anvil, it does the job well. One edge is rounded from heavy use of boxcar wheels, and the other is pretty square. Works out well depending on what I need. The ends are cut to a point on one and squared on the other.
This was a picture I took when I was shaping the 16ga to fill in my front fenders for the hidden latches on my tilt frontend. That's the old anvil on it's side with metal C clamped to the base: