Comment by a_shovel

I've heard this is part of why major infrastructure projects in America can be so expensive. A city builds one subway line, and everyone working on the project has no experience, so it takes a long time and is expensive. The expense convinces people to oppose any more projects, so the city doesn't build any public transit for a decade(s). By the time they're ready to build another line, all the experience has evaporated, so the new line takes a long time and is expensive. Repeat forever.