That’s a contributing factor. Their land mass, topography and general population density benefitted it highly as well, but the need to reconstruct their cities provided two problems that needed solving - fix the previous infrastructure and get the workers from outside the demolished zones into them. Trains existed for a lot of things already so it made sense to keep pushing them into the city centers. It was an inexpensive and reliable solution.
Never heard that theory but it makes sense. I just assumed they were denser and liked digging tunnels more.
That’s a contributing factor. Their land mass, topography and general population density benefitted it highly as well, but the need to reconstruct their cities provided two problems that needed solving - fix the previous infrastructure and get the workers from outside the demolished zones into them. Trains existed for a lot of things already so it made sense to keep pushing them into the city centers. It was an inexpensive and reliable solution.