Not sure how Elon Musk comes to the conclusion that digging one mile of a traditional tunnel costs 1 billion US$. The Gotthard base tunnel has a track length o

Not sure how Elon Musk comes to the conclusion that digging one mile of a traditional tunnel costs 1 billion US$. The Gotthard base tunnel has a track length of 35 miles and cost about 12 billion US$. It even consists of two separate tubes, each having a diameter of roughly 9 meters (much larger than the boring tunnel). If you calculate this, a mile of one tube of the Gotthard base tunnel (with a 2.5 times diameter of the boring tunnel) cost about 200 million US$, not 1 billion as claimed. https://en.wikipedia.org/wiki/Gotthard_Base_Tunnel https://en.wikipedia.org/wiki/Gotthard_Base_Tunnel