I found a really old nail/railroad tie with writing on it. How do I find out how old it is?

Anyone know of any archaeological websites or further info to find out how old nails might be? Thanks!I found a really old nail/railroad tie with writing on it. How do I find out how old it is?
I assume that you are referring to writing on a railroad spike. What does the writing say? What area was the railroad in. Both of those will be necessary to date the spike.I found a really old nail/railroad tie with writing on it. How do I find out how old it is?
try that one and there is more there too!:) good luck