There are now two high-profile major transportation projects promising fast trips between Los Angeles and San Francisco. One of them has a big unknown price tag and no known funding for the balance of it, is based on plans that don’t have all the details, and may never be built.
The other one is Elon Musk’s Hyperloop.
A comparison of that first transportation project – the years-in-planning high-speed rail project – to the Hyperloop, just announced Monday online to great aplomb, may of course be unfair. To the Hyperloop.
Yes, the Hyperloop is really a concept, and yes Musk announced that he doesn’t have time to build it, and yes there are a host of other unanswered questions and key bits of data we don’t have.
So how is this different than high-speed rail?
Before the high-speed rail folks fight back, let me say I’m not the one who made this comparison. It was Musk himself. Early in his proposal, he makes the comparison to high-speed rail:
When the California “high speed” rail was approved, I was quite disappointed,
as I know many others were too. How could it be that the home of Silicon
Valley and JPL – doing incredible things like indexing all the world’s knowledge
and putting rovers on Mars – would build a bullet train that is both one of the
most expensive per mile and one of the slowest in the world? Note, I am
hedging my statement slightly by saying “one of”. The head of the California
high speed rail project called me to complain that it wasn’t the very slowest
bullet train nor the very most expensive per mile.
The underlying motive for a statewide mass transit system is a good one. It
would be great to have an alternative to flying or driving, but obviously only if
it is actually better than flying or driving. The train in question would be both
slower, more expensive to operate (if unsubsidized) and less safe by two orders
of magnitude than flying, so why would anyone use it?
In fact, the Hyperloop concept is most convincing and detailed in making the case against high-speed rail.
Musk also makes a case for supersonic air travel as the best solution for connecting cities more than 900 miles apart. (Wouldn’t that be a great industry for some innovative Californian to revive, and make us a leader in?)
I had a harder time following things when he got into the details of how his Hyperloop would work to circumvent the Kantrowitz limit. The gist of it, for geeks out there:
… Mount an electric compressor fan on the nose of the pod that actively transfers high
pressure air from the front to the rear of the vessel. This is like having a pump
in the head of the syringe actively relieving pressure.
It would also simultaneously solve another problem, which is how to create a
low friction suspension system when traveling at over 700 mph. Wheels don’t
work very well at that sort of speed, but a cushion of air does. Air bearings,
which use the same basic principle as an air hockey table, have been
demonstrated to work at speeds of Mach 1.1 with very low friction. In this
case, however, it is the pod that is producing the air cushion, rather than the
tube, as it is important to make the tube as low cost and simple as possible.
That then begs the next question of whether a battery can store enough energy
to power a fan for the length of the journey with room to spare. Based on our
calculations, this is no problem, so long as the energy used to accelerate the
pod is not drawn from the battery pack.
Sound futuristic, yes. But high-speed rail technology exists, and it could take 30 years for that to connect LA and San Francisco, and that’s if the project goes forward at all.
So let’s take bets. Which will we get first – high-speed rail or the Hyperloop?
I’m taking the Hyperloop.