The transcontinental railroad only took 6 years to build and they did it primarily with hand tools and some explosives. How the hell does it take 30 years with modern construction techniques except because of union labor?
Politicians and their benefactors taking kickbacks, too. Look how many years and billions it took for that ridiculous “Big Dig” project in Boston. So much corruption that drives prices and completion time through the roof.
Most of the time and cost will be in figuring out how to design an inclusive bathroom within each car of the hyper loop.
The Hyperloop project is a bit like the Moon program in that physics says it is possible but it will still take many years and lots of cash to develop the technology and build the equipment and line. In contrast, the transcontinental railroad line was only a large building project that used proven materials and technology already in production.
The Transcontinental Railroad had virtually no cities or homes pr private land to negotiate and buy. However, if all of that was done up front, it would still take 25 years.
Don’t forget the Chinese were involved in that too.