> (While it's not made totally clear, I assume they're mostly finding stuff building stations, not tunnels. The tunnels are ~20m below ground, but the stations have to go all the way to the surface.)
This is exactly right. Rome's subway is famously dug very deep (30-80 meters) so the tunnels run under the ruins, but each station requires an excavation down to tunnel depth.
This is exactly right. Rome's subway is famously dug very deep (30-80 meters) so the tunnels run under the ruins, but each station requires an excavation down to tunnel depth.