Just thinking out load here (sort of...)
The tunneling would be the major part of the project.
A reflective mirror boiler should make team so reverse osmosis would not be required.
150# or 300# steam should supply most of the power needed.
Effluent steam could be re-superheated and piped to altitude, then condensed for the down hill trip to users.
I still think it is doable and much more realistic and needed than a Gov. Moonbeam train to no where... The 64 billion for the train would be a good start on building it.
Technically possible, absolutely.
Economically feasible, not even close.