Is Hyperloop positioned to take over where California High Speed Rail leaves off?
If the CAHSR project were to be abandoned, how much of the work could be repurposed to Hyperloop?Â The answer is, a great deal. Â In this hypothetical scenario, California gets a transport system better than CAHSR, but not as mind-boggling as Muskâ€™s original vision.
Californians get what they voted for
California voters would get what they voted for, a high speed transportation system that would allow schedules between San Francisco and Los Angeles in under 2:40.Â It would transit the route in the Central Valley, benefiting cities there, and potentially serving Sacramento.Â Would the Hyperloop be the same one Elon Musk described in his white paper?Â Probably not.Â It depends on what the CAHSR leaves, most specifically in track geometry.
The CAHSR described its general requirements for track geometry in a technical document dated 26 March 2009.Â Despite its title, Alignment Standards for High-Speed Train Operations, it is not a specification document, but rather a review of design standards from the United States and elsewhere.Â It does not provide any hard and fast standards for the engineering of the CAHSR.Â The closest it gets is describing Desired, Minimum, and Exceptional limits.Â While the definition of minimum might seem apparent, itâ€™s a fig leaf.Â The real minima are found in the exceptional column.
The curvesÂ make the difference
Both trains and Hyperloop have guideway design criteria that are based on the speed of the vehicle.Â The most important one is the radius of the curves.Â The speed at which a railroad train can negotiate a curve is based on two factors: the radius of the curve and the bank (superelevation or cant) of the track.Â In the United States, track cant is limited to a six-inch difference between the heights of the two rails.Â Given that limit, one can compute the radius of the turn.Â A Hyperloop has no limit on bank.Â Capsules could bank 90 degrees.Â As any rider of a roller coaster knows, the steeper the bank, the more g-forces you feel.Â So Hyperloop also has a minimum turn radius, smaller than that for a train at the same speed, but much larger for truly high speeds.Â Whether Hyperloop could use the rights-of-way negotiated for CAHSR depends on how fast Hyperloop wants to travel, how many gs passengers are willing to tolerate, and most importantly, what standards did CAHSR use when it laid down its final route?
CAHSR published the following table of turn radii.Â What is unclear from CAHSR documents is whether it expects to accommodate 250 mph travel over its entire route outside of Los Angeles and San Francisco.Â It is also unclear under what circumstances and for what percentage of the route the contractor will be allowed to use the exceptional and minimum standards.Â A CAHSR route with lots of exceptional curves and speed restrictions would be practically useless to Hyperloop.
In anotherÂ post, we calculated the minimum radius of curvature for a Hyperloop route that included 1.5 g turns (straight down into the seat).
CAHSR is planning 23.5 ft tall tunnels, so they are likely reusable.Â The stations will likely be unusable for Hyperloop.Â The catenary (power) cables for CAHSR would be of no use to Hyperloop.
CAHSR is planning ground-level rail for most of the path through the Central Valley, but with bridges and grade-separation for intersecting roads.Â Itâ€™s not a perfect fit for Hyperloop, but the right-of-way and access roads are big time-savers.
How might this play out?
Imagine that HSR becomes an issue in the next California gubernatorial election.Â Itâ€™s over budget and behind schedule, with no major funding in sight.Â Californians have lost faith.Â One of the Hyperloop companies has by then produced a prototype that operates at 350 mph on a test track.Â It asks for a hundred-year lease on the HSR right-of-way.Â It promises to relieve California taxpayers of any future obligation from the HSR project.Â The remainder of construction will be done by a commercial entity which will assume the risk for the remainder of the project.
After a new governor is seated in 2019 the gears begin to spin.Â In political fashion, it takes three more years to seal the deal.Â In the mean time, construction continues, so more of the route between Bakersfield and San Jose is developed: easements, pylons, power, and fences.Â Hyperloop has no interest in sharing tracks with Caltrain, so the original route through Oakland is revived.Â By 2022 HTT has opened a passenger line between Bratislava and Vienna.Â Hyperloop Technologies figured out how to move forty-foot containers between Stockholm and Helsinki.Â The two companies bid competitively to take over.
Not a perfect solution
Is it a perfect solution? Â No.Â The CAHSR route might limit Hyperloop travel to 440 mph, but thatâ€™s still twice as fast as the original HSR. Â California citizens get a high-speed transport system, but they donâ€™t own it.
All hope is not lost
If CAHSR isnâ€™t able to come up with a source for the remaining $44 billion it needs to complete its project, all hope is not lost.