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This Is How Elon Musk Can Build the Hyperloop
for a Tenth the Cost of High-Speed Rail
John Gardi is a
and jack-of-all-trades currently living in Canada. He garnered
himself a slice of internet fame when he made a mock-up for Elon Musk's
transportation system, and Musk himself dubbed it the "best
guess" he'd seen yet. Here, he elaborates on that guess, and explains
how Musk might actually build his Hyperloop—a "cross between a Concorde
and a rail gun and an air hockey table"—and do it for one tenth the
cost of California's high-speed rail project. –Ed.
My small part in the
Hyperloop saga began early in June when I tried to
visualize Elon Musk’s Hyperloop concept using
only MS Paint and a few scattered clues.
I thought that maybe a simple
infographic, bringing all those clues together in one place,
would help get folks back on track. (Or is it on tube?) I
did this mostly out of frustration with all the wild leaps that the
story had been taking...and still is!
What I ended up with was a
flow chart, a drawing that showed what I thought Hyperloop would do,
but not necessarily how it would do it. I avoided being too specific
about the how part of Hyperloop for a very good reason: When Elon Musk
was asked whether Hyperloop could work, his reply was that it
So, I’ll take the man
his word that he’s got ‘how’ covered. As Elon Musk has said about
himself: “There’s a pattern here.”
Anyway, I posted my flow chart
Twitter a few times but it got very little traction. (That was even
more frustrating!) Then Elon Musk finally dropped Hyperloop’s
reveal date of August 12th and asked for some feedback. I tweeted him
my flow chart, not expecting much to come of it. Very much to my
surprise, he responded within minutes, saying it was “the best guess so
It was then I
just what happens to one foolish enough to stick 'is hand in a
Many sites have
flow chart and I’ve been buried neck-deep in tweets and email ever
since! But generally, I did get what I was after: critical
discussion, a lot of which was a real help in formulating the ideas for
this very article. Thanks go out to all of you, too many to mention.
But one of those many
Brent Couchman, went the extra mile and rendered an accurate,
much tidier, version of my original flow chart. He even said
he’d take it down if I didn’t like it.
Quite the contrary! Here it is
Tinker’s original flow chart of Elon
During my heat wave,
Motherboard asked me if I’d like to write an article about
Hyperloop. I immediately jumped at the opportunity. At first I was
going to just do a recap to try to get things back ‘on tube’ this way,
but I’ve been thinking I can do Motherboard one better than that—and
take the discussion a step further.
believe that Hyperloop is merely a modern day version of the pneumatic
tubes used in banks, stores, and industry to move money and small items
over long distances or to other floors of a building. They’ve been
around for over a century, though not so much these days. There is only
one in my town that I know of, and it has fallen into
disuse. One reason I think Hyperloop is simpler than folks
think is that Elon Musk has resurrected another technology from the
depths of time, one that was a contender once, too: the electric car!
The main focus of this
be to show how we might accomplish Elon Musk’s claim that his
Hyperloop concept could be built for a 10th of the
cost of California’s proposed high speed rail. Using
technology no more complicated than warehouse building, I'll
discuss how the Hyperloop's main
line between Los Angeles and San Francisco might be
constructed well within Musk's estimates.
I’ll describe an overall
well as construction techniques—since the main line will comprise the
bulk of Hyperloop’s hardware, this will be where cost reduction matters
With what clues we allknow
now, I do believe I can make a pretty good
educated guess about how Hyperloop’s main line
could be built and why it could be done cost
effectively. There’s a lot we can extrapolate without having to augur
down into the nuts and bolts of Hyperloop’s specific technologies.
I’ll leave that
Elon Musk himself on August 12th.
But before we can even begin
design work, we need to get a sense of scale of the entire
Hyperloop system—some idea of how big to build it in the first place.
Finding that sense of scale will give us the clues we need to determine
how to design Hyperloop’s main line.
All aspects of Hyperloop’s
design will be driven by how big everything has to be made.
Scale is used to describe how an object’s size and/or weight
relates to the world around it. The scale at which something
is built also strictly determines which materials and techniques will
best be suited for that particular situation. Engineering is a complex
field and the scale of things is one of the main reasons for
that. I should point out at this juncture that I am not
a structural engineer myself, more civil (in both meanings of the
So, what we need to do is just
some way to get a grasp on Hyperloop’s scale so that we can know where
to start—or we’re stuck.
Scale can be used to describe
difference in size and/or weight between objects as well. In our case,
we need to compare railways and Hyperloop to find the difference in
scale, or scaling value: how large and/or heavy they are relative to
We can use a high speed rail
for one side of our comparison, but do we know enough about Hyperloop
to find a known value for the other side? If we knew how much a single
Hyperloop Pod weighed, for instance, we’d have a way to make that
But first, we need a baseline,
something in common between the two that can help us find our scaling
value. Luckily, Elon Musk was kind enough to give me a baseline in his
response to my tweet:
Using this new clue as our
believe it or not, we can now divine the scale of Hyperloop’s Pods by
size and weight! Using that, we can determine the scale of the entire
Hyperloop transportation system.
If, as we’ve heard, Hyperloop
can carry six passengers and we now know that they are six feet in
diameter, we can safely assume that each pod is about the size of a
family car and about the same weight too!
So it looks likes our
baseline of a six-foot pod diameter has actually given us the clue we
needed to make our comparison and determine the weight of a single
Finding this out will be very
important because the weight of the individual pods helps us determine
the ‘maximum loading’ on the entire Hyperloop structure. This, in turn,
tells us how strong everything has to be made. The maximum loading we
decide upon will tell us how much weight our main line structure can
have on top of it before it collapses.
We can easily work out our
value now! Thanks, Elon!
The weight of a high speed
coach is approximately 40 tons. The average family car is only around
two tons. Knowing this, we can extrapolate that Hyperloop could have as
little as a 20th the maximum loading of high speed rail. If we choose
our maximum loading value to be a 10th of high speed rail instead, our
building components would be twice as strong as they need to be!
In terms of safety, this is
So, for the purpose of this
discussion, we’ll use that value—a 10th the maximum loading of high
speed rail—because we probably can afford to, but also because we can’t
afford not to, considering where we intend to build.
Our chosen maximum loading
seems to jive nicely with that 10 percent cost claim of Elon’s
too…with a high margin of safety as a bonus! So far, so good!
The maximum loading value
whole design process from this point on. We should now
be able to determine the best economic, materials and, especially,
logistic choices with which to build Hyperloop’s main line.
How Railways Are Built
But first, to give you some
perspective, let’s take a quick look at how a traditional railway is
Workers must go over the same
worksite many times:
first, to clear, span and blast a
then to engineer drainage,
then to grade
and, finally, to lay down the
Each and every step of the way
energy, labor, and equipment intensive. Many different types of heavy
machinery are needed as well, expensive to buy and maintain. Megatons
of materials have to be moved around and that costs money too, even if
it is by rail.
Railway construction sites are
also called railheads, and are quite literally the
end of the line. The railway leading to the railhead makes it very easy
to get supplies and labor just to where it’s needed most. This is
sometimes called bootstrapping. By building the railway in front of
themselves, the construction workers are metaphorically pulling
themselves up by their own bootstraps, as it were.
It’s also the only
construction technique I’ve adopted from the rail industry for my
design—with improvements, big ones!
Any big project needs a good
business plan from the very beginning to succeed. The economic planning
behind the overall design is the most important factor determining
success or failure. Choosing the wrong design from the start could lead
to financial ruin. Overlooking a counter-intuitive design means you
might miss out on major cost savings.
The economics behind a design
be solid, not before the shovel hits the dirt, but before the pointer
hits the CAD screen.
chosen is to leverage our low maximum loading value so that Hyperloop
can not only outperform high speed rail but out-bid it
in the marketplaceby an order of magnitude—or
more, fair and square!
My choice for a potentially
successful Hyperloop main line design for is an elevated right-of-way
along its entire length. This is my ‘killer app’ for reducing
the overall costs of the main line portion of Hyperloop. The primary
reason this might work is that Hyperloop’s much lower maximum loading
value opens up new materials and construction techniques simply not
available to the rail industry.
Having an elevated Hyperloop
line also completely avoids or reduces many of the pitfalls of
ground-level right-of-ways, and opens up some new
opportunities as well:
The crossing of other right-of-ways,
roads and railways, will be a breeze.
Rivers and other terrain obstacles
be a 10th the problem of rail construction.
Hyperloop can avoid tunnels completely
having more flexible choices of right-of-way.
An elevated right-of-way opens up new
options, like leasing farmer’s fields using contracts similar to what
wind-power companies sign.
That could be paid for by leasing
Hyperloop’s right-of-way to communications companies for fiber optic
cables, cell phone towers, etc.
…and let’s not forget the solar power
couple of square miles of surface area can generate!
I could go on, but I think you
the picture. Building Hyperloop’s main line elevated could not only
reduce construction costs, but provide ways to monetize the
right-of-way beyond just moving folks from one place to another.
I’ll use only four major
components for my Hyperloop main line design:
Concrete pylon footings set
the ground every 300 feet* or so.
Pylons that go on top of the
footings, 40 feet tall to 100 feet tall.
Trusses that span the tops of
pylons, 300 feet long, 9 feet wide.
Finally, tube sections, that
atop the trusses, 18 foot wide, 9 foot tall, length unknown (due to
as-yet undetermined factors).
(*Measurements for reference
The tube sections are the real
of this show. These are the twin tubes and their associated hardware,
like solar panels and such, that are the business end of
Now would probably be a good
address earthquake mitigation. Put simply, I easily found engineering
solutions for each of our four building components and some dynamic
ones too. So, like Elon’s specific Hyperloop technologies, I can safely
leave the how of earthquake mitigation to the experts. I
consider the issue a done deal—and our 100 percent safety margin
doesn’t hurt us any either!
Building an elevated Hyperloop
line can open up still more ways to reduce costs
by taking advantage of standardization, modularization and
We can standardize components from the
Modularizing components into
would allow everything to be shipped by truck to our staging and
assembly areas. (SpaceX gave me that idea!)
Being able to ship by truck means
could be farmed out to multiple medium-sized factories, which
should help firm up the supply chain some.
Ground-level construction is limited
excavating and pouring the pylon footings. They should be simple enough
so that we could utilize local concrete contractors.
Once the pylon footings are complete,
everything else is from then on is just crane work. (Very interesting
So far, we’ve seen nothing but
economic advantages by building our Hyperloop main line elevated, over
railways themselves and railway construction too:
Based on our scaling value, given to
Elon Musk, materials by volume shouldn’t be over 10
percent that of rail construction at the very least,
Materials by cost, on the other hand,
be higher, but because there’s less of it, shipping and final assembly
costs should be much lower!
By minimizing ground-level
can reduce labor and materials costs big time!
Workers wouldn’t have to go over the
work-site nearly as often as in rail construction.
We can monetize beyond just moving
around to help cover operating costs!
We need only four major building
Economies of scale, where mass producing near identical parts lowers
manufacturing costs, help us here.
We can modularize our building
our advantage. Linked with economies of scale, this can provide the
basis for a robust supply chain.
From an economic standpoint
building an elevated Hyperloop main line seems like a pretty good
direction to go (pun intended).
OK! Let’s take that direction
and see where it leads us, so that we can get
those shovels into the ground—for what little shoveling we’ll be doing,
Before I discuss my materials
choices—or lack thereof—I’d like to point out something I discovered
while doing research for this article. I was cryptic before about the
amount my design should save on materials volume because I found that
my original estimates were way off! It was foolish of me to think that
my material’s volume would be 10 percent that of rail
construction. It’s actually about a magnitude lower!
those visible rails and ties, which are heavy all by
tons and tons of gravel to provide
waterworks to make sure the rail-bed
trestles that have to be built to
hundreds of tons of loading
and let’s not
forget tunnels, the bane of railway construction
budgets everywhere, and the megatons of materials they
Compared to railways,
Hyperloop’s main line would be an ultra-light transportation
I’ll have to admit, I’m open
suggestions for what types of materials to use for most of our building
components. Hey, a footing’s a footing. It’s concrete! Ditto
for the pylons and trusses too. Lots of choices out there.
Way back when, for a
drafting class in college, I designed a warehouse that spanned a little
less than the 300-foot distance between our pylons. A single truss from
that design had a maximum loading value twice that of what’s needed for
So, that leaves just one
component left to go—the tube sections—which I actually do
have a suggestion for:
Lightweight composite sewer pipe, 11 feet in
is easily handled by standard equipment.
Look, we knew from the get-go
we were gonna be stuck inside an oversized drain pipe for half an hour
anyway, so why not use a real one? (New, of course!) But
seriously folks, it really does make a lot of sense. We need strong,
lightweight tubes. Lots of them! Pipeline manufacturing companies are
only just now experimenting with pipe diameters smaller than what we
need, so that’s out. Someone suggested using new super-strong formulas
of concrete, but I think that would be overkill and dip into our
generous safety margin as well (which I’m loathe to do!).
Lightweight composite sewer
already exists in diameters larger than what we need (see image above).
Composites can easily be added to, modified and adapted to our special
purposes in a free-form way. (Hint: glue stuff to it!) If
these sewer pipes can handle twenty feet of dirt and the vehicles on
top of that, they will take anything Hyperloop can throw at
them, as we know it surely will! Thousands of miles
of this stuff gets buried in the ground every year.
It has potential. It’s
Oh, did I mention that
composite sewer pipe is affordable?
Now that we have at least some
about what materials are needed to construct Hyperloop’s main line, how
can we make good logistic decisions that optimize for cost reduction
during the construction process?
Logistic planning is where we
everything together. Contingency is where you plan for when things go
wrong. If you can’t plan for something, plan
around it instead so that it never happens in the first place! But be
forewarned, if you don’t plan for contingencies, you will get bitten!
I can’t emphasize how much
logistic planning matters to the bottom line at every stage of a big
project, especially during the construction/assembly phase.
Seamless deployment is the
a good logistic planner.
One example of how we can
logistically optimize for cost reduction is to build flexibility right
into our components:
Custom fabrication of variable height
could reduce the impact at ground-level by requiring far less ground
The greater the difference between the
shortest and tallest pylons, the more flexibility there will
be in choosing an economical right-of-way.
Our low maximum loading value suggests
the pylons could be up to 100 feet tall and still be affordable (with a
70-foot pylon height being the best fit value, the most economical
average height in this case).
We can’t expect a perfectly
run between Los Angeles and San Francisco either, so our trusses will
need custom fabrication too.
Trusses could be of variable lengths
well, if that helps reduce overall costs.
Being the 21st century and
don’t think any of this will be a problem. For environmental and
economic reasons, we really should place the pylons as far apart as
possible without compromising safety:
Railways rip a ground-level
straight through anywhere they need to go, destroying everything in
their path to do it! ‘nough said!
Compared to rail, an elevated right-of
would have minimal environmental impact on the ground and in the air
too! Unlike a wind turbine, Hyperloop has no external moving
parts. (Note to Elon: consider Hyperloop bird
The further apart the pylons are, the
ground-level work to do and less materials are used, proportional to
how many times the main line touches the ground.
I should point out that
material costs by being able to span those long distances between
pylons is just one reason to use our trusses (which might, at first
glance, appear to be redundant).
There’s other optimizations I
mention, but they all pale in comparison to the
cost reductions achievable from our killer app’s role in the actual
assembly process of Hyperloop’s main line!
How to Build a
The four easy steps of hyperloop
The actual assembly of
Hyperloop’s main line is really quite simple: After
the concrete pylon footings are poured and the Pylons erected on top of
them, final assembly of the main line can leave ground-level entirely!
The killer components of this
logistical high-wire app are those seemingly unnecessary
But surely, you say, the tube
sections could be made to support themselves, so why bother going to
all the trouble and expense?
Here’s why: Once the
first truss spans the tops of two installed pylons, we have a
ready-made work-platform from which to build the rest of
Hyperloop’s main line. It’s now that we’ll leverage that
centuries-old tradition of building railways by their own
bootstraps—except that we’ll be able to lay trusses and tube sections a
hundred times faster!
First, we’ll put a mobile
top of the trusses with a long crane attached to the front. We’ll call
it a truss crane, a specially-made self-loading vehicle that
can carry completed trusses for installation between our finished
pylons. It will move along the tops of the previously installed trusses
themselves, just like a railcar!
Once the truss crane
reaches the tube-head at the end of the last installed truss,
It plucks a truss from the flatbed
places the truss so that it spans the
directly in front of it,
secures it (by however means),
rolls out onto the newly installed
Truss to the
Trusses would be shipped by
short sections to staging areas every truss crane
load along the right-of-way (whatever best fit value
works). They are then assembled into full-size trusses. When the
truss crane installs the last truss of its load, another load
of pre-assembled trusses is waiting for it at the foot of the pylon
it’s located at. The truss crane only has to stop long enough
to reach down, grab, and then transfer the trusses onto its flatbed.
Handle logistics just
right and that’s the longest the truss crane will have to stop
during the entire main line assembly process!
The speed of laying trusses is
limited only by the speed of the crane and the efficiency of the supply
After all the trusses are
the pre-fabricated tube sections are placed atop the trusses
from more centralized staging areas. Since we already have a fully
functional right-of-way along the whole length of our
main line, the staging areas for the tube sections can be a
best fit to our advantage (whatever that happens to be). Once in
position atop the trusses, the tube sections would be rolled down the
main line’s right-of-way to their final destination, connected together
in sequence and, finally, locked down.
The tubes sections would use
same guideways that the truss crane uses to install the
Assembly of the
Hyperloop’s main line is now complete!
You see? Simple!
There you have
my rationale for using the trusses. By adding an extra
component to the overall design, we’d save money
over the entire project and not just the construction phase either!
Those trusses would more than pay for themselves by an order of
magnitude compared to any other construction
Let me count the ways…
The trusses are the
work platform for
truss crane so that we can utilize the bootstrap method.
The ungainly tube sections can now be
to their final destination down a finished right-of-way.
Since the truss cranes and
share the same guideway, then conceivably both parts of assembly could
take place at the same time.
be removed and replaced as easily as they were installed when new,
better technology comes along (as we surely know
So you see, by incorporating
trusses into the design from the beginning of the design process,
construction, maintenance and even complete replacement of all the tube
sections becomes so much easier, quicker and cheaper!
And basically, that’s
My killer app—using an elevated Hyperloop main line right-of-way—was
not some exotic technology, but actually just a logistics scenario for
assembly that was built right into the final product all along!
If we can coordinate the
method with well-organized staging areas and some good supply
management, then Hyperloop’s main line would not only be
ultra-light, but ultra-fast to assemble as well.
The lesson here? Good logistic
planning trumps materials costs any day!
Now, just how
this design and method of construction? I didn’t find any
show-stoppers. Solutions for all the individual aspects of my design
are out there. I found them easily. You can too. It’s called Google.
Building an elevated Hyperloop
line should be no more complicated than building a warehouse, except
that our warehouse just so happens to be twenty feet wide and
hundreds of miles long! Since there’s never been a need to build a
warehouse by bootstrapping it, we are in new
territory here, but it’s certainly not insurmountable.
I found cost efficiencies
I looked too. Even adding a component—the trusses—brought the
(estimated) bottom line for construction costs down by an order of
magnitude… and, incidentally, increasing the costs of materials by a
Call me eccentric, but I’ve
considered cost savings, regardless of how I (honestly) achieve them,
to be among my many definitions of profit!
As for the self-assembly part
Hyperloop main line design?
as a construction method for Hyperloop? The only show stopper I can see
is the first word in that last sentence!"
So, having said that,
I’ll step out on a limb here (I do it all the time. It’s not so
bad.). Building Hyperloop’s main line for a 10th the cost of
high speed rail is not only feasible—it's doable!