You don't need to tear lots of stuff down to build public transit: you just have to dig tunnels. It's not that hard. The only place where you need to really t

You don't need to tear lots of stuff down to build public transit: you just have to dig tunnels. It's not that hard. The only place where you need to really tear stuff down is at the stations, and even here much of it can be done under existing structures. This has been done in America before: DC's subway system was built mostly in the 1970s.