Is this mentioned? It's crazy complicated underground in large old American cities. Been putting pipes etc under there for a couple hundred years. A Seattle tunnel got stalled for months when they hit an old service main iron pipe that'd been put there a century before and forgotten.

My sister worked for a pump company, been in business for 150 years. Got calls all the time for replacement pumps that had failed after a century etc. One was 6 stories underground in NYC. Had to dig a tunnel down through a maze of services (electrical, tunnels, drains, water, gas) to get to it. Then had to have exactly the same pump to fit exactly into the geometry it used to have (no problem; they still had the drawing for the pump in a drawer and made an exact copy). Pulled the old one up, dropped the new one down, hooked it up and then buried it for maybe another century.