> There is more underground distribution (medium voltage) in Europe because cities are denser and older and there's less space for overhead lines. Do you know

> There is more underground distribution (medium voltage) in Europe because cities are denser and older and there's less space for overhead lines. Do you know if the existence of other relatively large, underground facilities, namely subway railways, is a factor? Is it a common/reasonable practice to use a rail tunnel for (non-rail) power distribution? I can imagine it would the advantage of not having to dig for inspectin/maintenance but a disadvantage of needing to coordinate with rail operation instead.