It's all but impossible to walk past a loose (discarded) railway spike and not pick it up. You may toss it later, but there's something magical in the heft -- and history -- of these items.

In terms of their metallurgy, my understanding is that spikes are pretty low carbon. That makes sense; you wouldn't want one to fracture the rail while pounding or snap off during stress or cold and leave a rail loose. Blacksmiths like to play with them as "found materials" but they have the means to work more carbon into the steel to make a passable cutting edge.

But they're still fun to play with as rough hammers and general conversation pieces.