> Is Paris Metro so shallow because of the quarries?
The Paris metro is a mixture of deep, subsurface, and surface tracks. There are a lot of shallow tunnels mostly because cut-and-cover was easier and cheaper than digging deep underground.
Paris is very complicated underground. Besides the quarries there are the sewers, catacombs, some underground lakes, reservoirs, etc. It is definitely a complicating factor when planning new metro tunnels.
> When is Tim Traveller's video on the subject coming out?
You’d think exploring the closed parts of the catacombs would be right up his alley (actually I would be surprised if he did not try, even though he might not want to put that on YouTube). They’ve been cracking up on trespassers recently but it still is fairly popular with the urban exploration crowd.
The Paris metro is a mixture of deep, subsurface, and surface tracks. There are a lot of shallow tunnels mostly because cut-and-cover was easier and cheaper than digging deep underground.
Paris is very complicated underground. Besides the quarries there are the sewers, catacombs, some underground lakes, reservoirs, etc. It is definitely a complicating factor when planning new metro tunnels.
> When is Tim Traveller's video on the subject coming out?
You’d think exploring the closed parts of the catacombs would be right up his alley (actually I would be surprised if he did not try, even though he might not want to put that on YouTube). They’ve been cracking up on trespassers recently but it still is fairly popular with the urban exploration crowd.