Why the PNW Will Never Have High Speed Rail

 I live near Seattle, and I love it here.  We're a little isolated from the rest of the country, which is both good and bad.  One of the bad things is that it takes frustratingly long to get to any other part of the country.  If you want to get there in less than a day, you need to go by air.   It takes 24 hours to get to the nearest other region, the San Francisco Bay Area, by rail, or 13 hours by road, but only if you're lucky with traffic and break the speed limit a lot.

Lots of people advocate for High Speed Rail, and I am very much one of them.  An imaginary 200 MPH (300KPH) HSR system could get us from Seattle to San Francisco in 3.5 hours.  If the stations are near to your destinations, it would be practical to get to a meeting and back in a work day.  This isn't really practical by air unless you fly private--Airports are half an hour or more outside of town, and TSA adds 90 minutes or more.  Add that to 2 hours in the air each way and it adds up to 4.5-5 hours travel time each way.   Add that to the meeting itself and it's a 12 hour day or more.   Private Jets are slower, but not that much, and they subtract all of TSA, and they can be precisely scheduled--it makes the one day round trip possible, which it just isn't on scheduled flights.  So the people who can afford it, do so.

The Northwest has three big cities: Vancouver, Seattle and Portland.  Metro Vancouver has about 3.4M, Seattle, 4.2M and Portland 2.5M.  But those three cities are in a geographic island:  There's a huge mountain range between central Oregon and the Central Valley of California, and two even bigger mountain ranges to the east.  It's over 600 miles from Portland to San Francisco, and about 300 of them are really rugged terrain.  The SF Bay area has only about 8 million people: less than the PNW.  To make a High Speed Rail Corridor really practical, LA/San Diego, about 20 million people need to be added.  And once you've done that, you need to connect to the rest of the country.  Spokane, Boise, Helena and the other northwest cities are tiny.   You need to go down to Salt Lake City and Denver, or up to Calgary/Edmonton, to reach many folks.  

 There is already rail through all of these routes, but a lot of it is very far from being able to handle High Speeds.  Through the Siskiyous, it's barely able to handle moderate speeds and there are some radical twists and turns.  Making this capable of even 200KPH, will be incredibly expensive, much less 300.   A bunch of the existing route is comfortably able to do 80MPH--but less than half.  All the terrain north of Eugene will need to be moved into the Willamette/Cowlitz/Nooksak Corridor, and rebuilt to HSR standards.  The construction cost to do this is at least $100M/mile for the 700 miles from Eugene to Vancouver--$700B, and that doesn't factor in the cost to obtain the land and get other political clearances. Figure $2T.  Redding to San Diego is about the same: 700 miles/$2T.  Finally, you've got to do the mountains: Eugene to Redding is about 300 very mountainous miles.   That'll probably cost at least $2T, maybe even more.  

 Would it be worth it?   Perhaps.   The roadbed that's already in the various flat corridors will be cheaper to obtain than the portion that's not.  Near Seattle runs along the Puget Sound Coastline, and will be useless for our purposes--Everett to Olympia, well over 100 miles, and apart from the cities themselves, that's probably the most expensive land on the route.  Such a system will stimulate business enormously--but $6T is a lot of money: about 2 years GDP from the entire affected region.  

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 In the long term--surely not in my lifetime, we will have some form of VacTrain.  Hyperloop or maybe something even better.  Many pundits argue that this will be quite a bit cheaper than HSR, and I see their point: Hyperloop takes a tiny amount of space, and tunnels and bridges are much less substantial than for trains.  A Tunnel Boring Machine through the Sikiyous would solve a mess of problems.  Not sure it's possible, but it's an appealing thought.  Not just 200MPH.  1000 MPH.  Seattle to SF in 45 minutes, no waiting anywhere. 

Hyperloop Criticism

There are plenty of difficulties with getting a hyperloop or other vactrain system installed, but none of the criticism I'm seeing of the concept is correct.

For example, they give the example of a tank truck that is evacuated and is crushed in a fraction of a second by atmospheric pressure.  This is a shockingly poor example.  These tanks are intended to be filled under positive pressure, and the metal cylinder has thin walls (1/8" or so) which can hold the load because they are loaded in tension, but not in compression.  Any competent engineer would simply make the wall thickness sufficient to sustain this pressure.  This varies with different tube diameters but Musk's original paper did some calculations on this and it's a half inch or more.

This same thing would also make the pipe immune from most forms of attack from terrorists.  It would take a gun caliber 2" or bigger to punch a hole, or a pretty large focused explosion, through a pipe this thick.

Even if the pipe is punctured or develops a leak, all that happens is pressure is lost, and the vehicles within slow down and air friction increases.

Their solution for earthquakes is also simple and effective.  The pipe is attached in a way that allows its support to move on the pipe.  For quakes with movement up to  the compliance of the mechanism, nothing will happen at all and operation can proceed unaffected.  This is well over magnitude 6.  For a bigger quake, there's a chance the travel of the mechanism will be exceeded.  This won't break the pipe but there may be damage.  Vehicles in operation would slow down and might need rescue, but it's hard to imagine a scenario where an earthquake, even of magnitude 9 or more, actually killing hyperloop passengers.

Hyperloop Problems?

 I just watched Joe Scott's piece: What's Happening (And Not Happening) With Hyperloop | Answers With Joe - YouTube.   He gets some of it, but misses more.

He's right that a long vacuum is relatively hard to achieve, but he misses a lot of the point.

1: by making the walls of the tube thick enough, the tube can withstand a hard vacuum.  His example of a big tank truck being crushed by pulling a vacuum inside is irrelevant.  That tank was designed to take a slight positive pressure and has very thin walls.   There's a simple equation to determine the needed the strength to resist atmospheric pressure.  For a light bulb or small can, it doesn't need to be thick; it's more for a bigger tube.  Elon's paper talked about tubes with 1inch thick walls. (Crazy extreme: Triton Submersibles' 36000/2 recently protected it's pilots from a pressure of 16000 PSI with a spherical structure only 90mm thick.  This is over 1000 times the pressure difference a  true vactrain would need to tolerate a hard vacuum at atmospheric pressure.)

2: this is a lot of metal, of course, but it's actually quite cheap.  the rule of thumb is fabricated steel is 1-3$K per ton.  A 5 foot tube one inch thick weighs about 640 lbs per foot.  At $1K per ton, that's about $1.7M per mile.  Not free by any means, but a lane of freeway costs over $10M per mile, and the california HSR project was several hundred million per mile.

3: for the same reason, most of the threats from terrorists are implausible.  an inch of steel can withstand a shell from a pretty substantial cannon.  A terrorist with access to such a thing will be going after much softer targets.

4: small vehicles do not limit capacity.   Why is this so hard for people?  Small vehicles somehow manage to carry many times more people than buses or trains on our highways.  You need to have more of them, but they're cheap...especially on something like hyperloop where the vehicle is pretty much a passive object with life support and not much else.

5: a big part of the benefit of small vehicles is that they can be unscheduled.  There will be a queue of them waiting at the station, which unlike air travel can be in the city core, or even several stations placed around the city.  get in, tell it which station is your destination, and the computer does all the rest.  The vehicles don't move when they're not needed.

6: the long vacuum won't be cheap and there surely will be leaks, but they're not too difficult to track down.   as long as an individual leak isn't too big, it's just a small loss in efficiency, not a showstopper.

7: putting part or all of it in a tunnel is obvious.  since it's the steel tube that's maintaining the vacuum, digging the tunnel is the same problem as ever.  Burying it protects it from the elements to some extent, and provides convenient support, but it also makes it harder to work on.  This is the reason the (much harder) vacuum at giant installations like CERN have access all around.

8: Musk's team did an analysis of I-5 between L.A. and San Francisco, and for most of the route, speeds north of 700 mph are easy without pressing the passengers too much.  near the cities they'd have to slow down a bit because there are hills and waterways and buildings..  bottom line though is that their design would be able to make the nearly 500 mile trip in about half an hour.  Dallas to Houston is half that and a MUCH flatter route.

9: There are several designs for a track switch that will work for hyperloop-speed trains.  A magnetic version of the one Ed Anderson devised for Skyweb Express will work, and there are plenty of others that would too.

10: Unless there is significant damage for some reason, there is NO risk of derailment with any sort of vactrain.  Conventional railroads use a relatively tiny flange to keep the wheels on the rails--it  meant that the track switch could be relatively simple to make and manipulate in the 1830s.  Debris on the rail, damage to the flange or rail, brakes getting stuck on, pushing a train through a swittch the wrong way, etc, will all cause derailment.  Monorail, maglev, etc., do not have these issues.

Hyperloop Safety

Several of the detractors of Hyperloop have suggested that it's an attractive target for terrorists.  This is silly.  No more than a few dozen people ever accumulate at the station.  It's the same attractiveness as a city park or the lobby of an office building.  If you want to kill lots of people, Hyperloop is a difficult way to do it.

Lets look at a few cases:  The tube is steel, almost an inch thick.   A pipe bomb or other crude explosive, such as used in the Boston bombing, will barely scratch the surface.  A shaped charge might.  Somebody with a large gun--a tank, for example, could.  Rednecks taking pot shots can do little harm, unless they're using a Barrett 50 or bigger.  We're not really talking about "terrorists" doing this sort of thing.  This is a much more sophisticated operator.

What if they do manage to poke a hole big enough to cause loss of vacuum?  Well, they've just shut the thing down.  If a vehicle happened to be in the path of whatever did the damage, they'd be hurt, but any other vehicles would simply see a sudden rise in air pressure and the vehicles would slow to a stop due to air friction--if they're going at top speed, this could be several Gs.  By designing the vehicle so it's still pretty slippery in normal air pressure, passengers would be uncomfortable, but unhurt.  Get the passengers out and begin repairs.

I'm a lot more concerned about manufacturing errors and acts of nature than I am about terrorists.  A lightning hit could potentially cause some damage, although I'd think grounding it properly should be easy.  Manufacturing errors could cause splits, but they should mostly be slow leaks--and most of them should be discovered before it's carrying passengers.

The tube is stiff enough that if it's missing a few support columns, such as if a wayward truck ran into one, it should be inconsequential.   They should be fixed as soon as practical but there's probably no need to even shut the thing down.   Of more concern is if an earthquake or flood or coordinated attack damages a bunch of them.  The tube should settle gracefully to the ground, where it's most likely still operable.   One special case: the supports for spans that cross rivers or big valleys or such need to be specially hardened.  This is already true for more conventional bridges.

One particular vulnerability is the slowdown LIM.  By breaking the circuit, vehicles would still be going extremely fast at the end of their trip and crash into the station.  A certain amount of redundancy can make this more difficult to attack and reduce the chance of malfunctions.  In a worst case scenario, the tube can be opened to normal air pressure and the vehicles will slow down pretty quickly.

The vehicle carries a large battery, which powers life support and a large fan, which propels the vehicle enough to maintain speed in near-vacuum, and lifts it.   I suspect this can be made to still work in normal atmosphere, but it won't propel the vehicle very fast.   The system should be designed with emergency exits every few miles.  The vehicle would move along to the nearest and stop.  There should be a mechanism which allows the passengers to get out and then move the vehicle further to allow another vehicle to use the same stop.   I suspect the emergency exit would be integrated with expansion and other sorts of airlocks.  more on this in another article.

What happens if the vehicle itself loses power while the rest of the system is still fully functioning?   It slows down--potentially fairly rapidly, depending upon how fully power is lost.  If other vehicles are still functioning normally, the next in line will smack into it pretty fast.  So there needs to be active communication between vehicles.  If one slows mysteriously, or contact is lost, the ones behind need to slow, until they figure it out.  It may be necessary to have some alternate way of moving the disabled vehicle--e.g. the one behind pushes.   I'd hope to avoid this but it may be necessary to allow the system to come to atmospheric to recover the passengers in some cases of failed vehicle.    Obviously it's worth a great deal of redundancy to minimize the chance of this happening.

Hyperloop

This is a topic that interests me a lot, so I expect this will be the first of many posts.

Elon Musk and team have posted his "Hyperloop Alpha" essay today.  It's not quite what I'd thought (I thought Vactrain) but it's close.   They've done quite a bit more than "envelope" level engineering but it's still very far from something that can actually be built.  There are a lot of appealing concepts, and the most appealing of all is that he's beginning to work out costs and they're surprisingly reasonable--under $8B for the initial SF-LA route.  This compares with $65B for the proposed High Speed Rail with roughly the same service and less than 1/3rd the speed.

It consists of a pair of steel tubes, normally elevated, which are evacuated to 0.015 psi.  This not quite a hard vacuum but "soft" enough that relatively ordinary equipment can be used to maintain it, and some tiny leaks can be tolerated.  This is about the same pressure as a spacecraft flying at about 30 miles would feel.  Pretty low drag, but far from zero, especially at the proposed 760mph, approximately 1/1000th of sea-level drag.  The vehicle is substantially smaller than the tube (roughly 30%) and has on the front a big fan, which sucks in air.  Most of this is spat out the back, helping to keep it going, but a little is squeezed out the bottom through what they call "Skis", which ride on the floor and sides of the tube, generating a cushion of air to ride on.  This is familiar to people who play air hockey, and it's been used in lower speed transit before, such as the people mover in the Detroit Airport.

The low pressure in the tube means that it doesn't take a lot of power to overcome air friction and can be sustained by on board batteries (using numbers gleaned from their work with the Tesla S), and the big power drain from acceleration is accommodated by Linear Induction Motors (many existing transit designs use LIMs, such as the Vancouver Skytrain).  These are mounted in the tube and the vehicle itself is passive.  They are also used to decelerate the vehicle, recovering a large fraction of the energy used.  They propose mounting solar panels on the guideway and calculate that those and a rather minimal amount of battery storage will fully power the thing.

They've actually done quite a bit of engineering on the support columns, concerned (it being proposed for California) about earthquakes.  They allow the tube to shift freely a little bit relative to the support in three axes and have the ability to make more permanent adjustments to accommodate shifting terrain.   The propose most of the route down the center divider of Interstate 5.    They'd first connect LA and San Francisco, and later add extensions to Sacramento, Fresno, San Diego and Las Vegas.  Most of the trip would be at 760mph, handling the curves required by the hilly sections near the ends at 550 and 300 mph, leading to a time en route of 35 minutes.

The vehicle itself is a low tube, with the fan section and associated mechanism at the front, and 14 pairs of very recumbent seats for passengers on either side of a big central longitudinal hump.  The whole thing is less than 5 feet wide.  They would depart every few minutes, unscheduled.

The have a separate design which is big enough to carry cargo, including three cars.  It requires a bigger tube.  They seem mostly to be concentrating on the smaller one.

This seems silly to me.  The size of the vehicle is limiting for a lot of people: elderly and other sorts of low-mobility people will need considerable assistance to get in and out of the seat, and even fully able passengers are trapped there for the duration.  A child requiring assistance will be fairly far from their caregiver.  There's lots of necessary luggage that could easily be accommodated with vehicle that's just a little bigger: wheelchairs, bicycles, etc.  Making it big enough to handle a passenger in a wheelchair will allow people to move around a little, including relieve their bladder, caregivers to help children and disabled, ease entry, and more, while only growing the overall size of the vehicle and structure 20% or so.

Our Transit Future

This is speculative.  There's a fair bit of engineering to be done for some of this, but all are completely possible using today's technology--albeit expensive.  There are no breakthroughs required, just the will to do it.  In several cases, they are extremely cheap to operate, while being expensive to initially build.

For the longest, fastest trips, we will use Evacuated Tube Transit, or VacTrains.  Traveling in evacuated tubes at thousands kilometers per hour, it takes so long to accelerate and decelerate that it's impractical to share tubes between different routes in most cases, even when they're roughly co-linear.   Thus these will be largely point to point routes, initially between our biggest cities, passing under oceans, over or through mountains.  There are a lot of difficult engineering problems still to be solved, but the advantages are so large it's hard to imagine this technology won't eventually be adopted.  Trips will be in relatively small vehicles, unscheduled, provided as demand requires.  Energy use is extremely low--there's no air drag, and rolling friction is negligible (they'll probably use maglev).  Once the thing up to speed, it's traveling on momentum until it's time to slow down--and you can use slowing down to generate power!  Imagine: New York to Sydney in an hour, leaving any time you wish. 

Intermediate distance travel will be implemented with High Speed Rail which resembles the current form, possibly using maglev, traveling at a few hundred kilometers per hour between cities no more than a few hundred kilometers apart and probably no less than 50.  It's almost as expensive as VacTrain to build but because the trains are atmospheric they can't run more than about 500kph.  Because there's a power and aerodynamic advantage to it, trains will be long and run on schedules.  All of today's HSRs are electric and I see no reason to think that might change.

Conventional Aviation will serve routes that are not yet served by VacTrain or HSR.  Over the long term, these will more resemble regional airlines than the majors.  Aviation has amongst the highest energy demands of all and will thus remain one of the few users of Fossil Fuels and their artificial replacements.

Ballistic travel is possible.  The technology used to put people into low earth orbit and return them safely can also be used to provide point to point travel anywhere in the world at speed as high or higher than evactuated tubes, and using it that way will allow economies of scale to reduce the cost and increase the safety for both types of destination.  Rockets consume a lot of fuel although some use non-fossil varieties.  I think it is really only practical if there's also a significant business putting people up into low earth orbit and recovering them.  I think this can only happen if there are meaningful (read: profitable) space colonies, probably mining asteroids.

Conventional interurban or commuter rail will serve high volume corridors that are too short for HSR or VacTrain.  Some existing rail is powered by Diesel, but much is electric and over time I'd expect these corridors to be electrified (or re-electrified).

Personal Rapid Transit will largely replace municipal bus, light rail and subway systems.  Where practical and grade separated, this will occupy the rights of way those systems used, with a cheaper, faster, more convenient alternative.  You can get four PRT lines into the space occupied by a single subway track, and since most of these are two way, that means as many as 8 PRT lines.  Since each of these has roughly half the capacity of the subway, that means a net doubling of line capacity.    It's far more than is necessary in most places.  Building new PRT routes will be far cheaper than anything except bus routes and they are easy to connect up with existing PRT routes.  PRT can serve some intercity routes, but probably no more than 50km or so.

Battery electric cars will completely replace carbon combustion cars.  These are practical for short routes that are not yet PRT-ized (or so lightly traveled that they will never be PRT-ized).    A few examples:  very low  density dwelling--less than two or three people per acre.  Point to point service for handicapped.  (PRT is much more amenable for handicapped than conventional autos but there are some situations that just can't be helped).   There will be plenty of ambulances and other rescue vehicles serving the PRT, but some need to serve other houses.

A bus is just a big car that carries a lot of people and runs on a scheduled route. Routes that are not PRT-ized, such as low density rural areas, may have a battery or fuel-cell electric bus on it, very much as today.  Buses are much more amenable to fuel-cell energy density issues than are cars.

The biggest present problem with battery electric cars is that they can't be used for longer trips.  The solution to this is better roads: Provide a charger that travels along with the car as it drives on a longer trip.  This probably consists of a dedicated lane on certain roads (I think the present US interstate system is a good place to start) which has some sort of power lanes.  When you drive on it, you surrender control of your car to the computer and it couples to the power system and recharges your battery as you drive, billing you by a system resembling the current RFID passes used for Toll Roads and Bridges in some places.   Because the computer is driving, and traffic is grade separated from human controlled traffic, the speed limit can be whatever is practical for the road, unlimited by driver limits, and the cars can drive close enough to the one ahead to take advantage of its aerodynamic draft without risking the driver ahead doing something unexpected.   When you want to get off, you press the button and the takes takes you off the special lane and merges you with the human-controlled traffic, and hands over control.  Travel by car between most urban areas will be a lot slower and less convenient than vactrain or HSR, but there are a lot of reasons you might want to drive--sightseeing, for example.

Freight can be moved by many of these same systems.  Most larger facilities will have their own PRT freight dock.  PRT freight can intermingle with human traffic up to the capacity of the system.  PRT freight can be unscheduled, providing Just In Time delivery for almost all goods.  This actually reduces the size of loading docks, while increasing their capacity quite dramatically.  I think there's an application for a Less than Car Load transfer points: a container drop off point which transfers directly to PRT freight vehicles without going inside a building.  The container serves as a sort of temporary warehouse.

Smaller buildings won't have their own PRT station, so if you need a large item delivered--a refrigerator for example, this will still use a delivery van.  Except for being battery-electric powered, this will be just like today's vans.  Small deliveries will use couriers riding in the PRT and walking the last few hundred meters, possibly with a cart.

The other modes can also ship freight, although it'll be more like air freight.  If it's heavy and large, it's probably better to use conventional containers, on trains and ships.  Most of these can be electrified, so they can get their power from renewables, but there's little application for shipping a sofa halfway around the world at 5000kph, although there clearly is a market for documents and other small objects.  Long Haul Trucks and Containers should mostly be shipped by train, although something resembling the current long haul truck system can be electrified using the power rails for electric cars.  This presents a special wear problem for the dedicated lanes that needs to be resolved.

Petroleum, natural gas, and artificial fossil fuel like fischer-tropsch or algae or ethanol, will still be used for airplanes, and probably some other specialized vehicles needing high energy density (I'm thinking of a pumper fire truck) but it will probably cost $50/gal or more and will only be used where there really is no alternative.  Most human and freight transport will be done in vehicles that get all the power they need from their guideway.  Battery electric vehicles have a range of 70 miles today and with frequent charging stations and charge-while-you-drive solutions, their effective range can be infinite.