Fantastic writing. So a structure exists... few pause to contemplate the sweat, toil, pain and sometimes death that went into it's creation. Much like old sayings such as, 'If these walls could talk' and so on. To some it's just a railway stretched out across the landscape and to others it is a monument to humanity.
I'm reminded of something from the original Kung-Fu series about a man who spent his whole life finding stones, pieces of glass and other things and building a monument in some town square. The old man died and the lead character asks his master something about the old person accomplishing nothing more than a pile of stones. The master asked, 'Is it but a monument.... or is it the man? ' That always moved me and I haven't been moved that way since. At least not until I read your poem. So once again... fantastic.