Question! raises hand

I have a question, but I'll put it in an LJ-cut just in case of spoilers.

How old is Hohenhiem? I don't quite understand because he knew there wasn't a railroad, but Lieutenant Ross said it was more than a hundred years ago. That means he's more than a hundred years old or something. o_O; But that's weird. He looks like he's around his 40's.

Thank you! :)