Musk could help with the back end of the problem. The TBM up front gets all the attention. Behind the TBM is usually a temporary two-track narrow gauge railway line, with muck cars carrying dirt and rock out, segment cars carrying tunnel wall segments forward, plus tool cars and worker cars now and then.[1]
Hanging off the back of the TBM is all the machinery to move all those heavy items around.[2] Including the machinery for laying more railroad track behind the TBM.
Self-driving electric muck cars, segment cars, etc, might replace that temporary rail infrastructure. That's something Musk's company could address.
The back end of the process seems to get less attention than the front end. Most of the length of the TBM is devoted to material handling, though, as is the rest of the tunnel all the way back to the entry. A big fraction of the cost is in moving all that stuff around.
Hanging off the back of the TBM is all the machinery to move all those heavy items around.[2] Including the machinery for laying more railroad track behind the TBM.
Self-driving electric muck cars, segment cars, etc, might replace that temporary rail infrastructure. That's something Musk's company could address.
The back end of the process seems to get less attention than the front end. Most of the length of the TBM is devoted to material handling, though, as is the rest of the tunnel all the way back to the entry. A big fraction of the cost is in moving all that stuff around.
[1] http://www.zslocomotive.com/products [2] https://youtu.be/SY3Q9GqUYro?t=115