
Japanese railway company starts testing 249mph bullet train speeds - pulisse
https://arstechnica.com/cars/2019/05/japanese-railway-company-starts-testing-249mph-bullet-train-speeds/
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cheerlessbog
Faster trains make longer distances competitive with air travel. Assuming a
similar price per mile, the cutoff is T * deltaV where T is the extra time to
travel to and from the airport and get through security and deltaV is the
difference in speed. Assuming 3 hours and 250mph (500 - 250) the cutover is
750 miles.

Reality is less simple as price varies as well. In Europe the cutover (in time
and price) seems about 200 miles [1] although the CO2 emissions are up to 30x
higher by air. Of course speeds are lower, maybe 150mph which would suggest a
450mi cutoff.

[1] [https://m.dw.com/en/trains-vs-planes-whats-the-real-cost-
of-...](https://m.dw.com/en/trains-vs-planes-whats-the-real-cost-of-
travel/a-45209552)

~~~
sandworm101
>>> Faster trains make longer distances competitive with air travel.

There is more to this competition than raw speed. There is also capacity and
environmental footprint (carbon per passenger). Aircraft have different
logistical advantages. An airport runway can handle far more people than a
rail line. Airports can land a plane every minute. A rail line would never
dare have two high speed trains that close to each other. So, as a link
between two points, a pair of airports can move more people than a train in
most circumstances. That is a type of 'faster'.

Trains would normally win on carbon footprint, but bullet trains don't run on
solar power. Their carbon footprint isn't zero. And one must consider total
journeys. If the train infrastructure is widespread, great, but it often
isn't. Dropping a new airport somewhere is far cheaper (in every regard) than
plowing a new rail line through the countryside. It may work in Japan, but I
doubt trains will be connecting Vancouver to Calgary anytime this century.

~~~
MagnumOpus
> An airport runway can handle far more people than a rail line.

Definitely false. The most efficient runways (say Gatwick) manage 8-9,000 pax
per hour, with a huge chunk of departures delayed due to runway congestion.
The Tokaido Shinkansen line manages more than 20,000 per hour and most are on-
time (and could run at night because noise is less of an issue).

It helps that 750-pax trains take a minute to board and can be run every 3-4
minutes if needed.

~~~
sandworm101
Not bullet trains. As speeds increase, the safe distance between trains (both
in time and space) must also increase. No rail line (line, not station) can
handle one bullet train every minute. A large railway station can indeed
handle more than a single runway, but apples and oranges. A rail station can
have multiple rail lines just as an airport can run multiple runways.

~~~
ericd
Maybe not every minute, but in Japan, the same track can handle a new bullet
train every few minutes, like clockwork. The throughput is enormous. And the
footprint of a track is much, much smaller than a single runway, so it's not
uncommon for even modest rail stations to have 15+ tracks. Chicago O'Hare has
the most runways of any airport in the US, at 8, and they aren't all usable at
the same time, since they intersect, and wind direction varies. And that's an
enormous facility.

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CPLX
Meanwhile, we still can’t take the subway to LaGuardia despite a few billion
dollars in recent renovations.

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bamboozled
That is pretty unbelievable honestly

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sneak
The Las Vegas monorail is on the same side of the strip as the airport. It
doesn’t go to the airport.

These systems are working as intended. It’s about extracting money from
travelers, not time savings or energy efficiency.

I would be astounded if there weren’t overt or covert flows of cash from the
taxi companies to the decisionmakers that blockade these projects.

~~~
djsumdog
I was really surprised the monorail didn't get to the airport. I suspect Taxi
companies originally lobbied to make it that way.

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Gibbon1
In the US the Airports, Taxi companies, Muni's buses, and commuter rail
systems are all Balkanized fiefdoms.

They all really need to be under one thumb.

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viseztrance
The title is misleading. These trains will have an actual operating speed of
360kph (224mph). In contrast, the fastest shinkansen trains (hayabusa)
currently operate at 320 kph. It's still a solid speed increase but not as
ground breaking.

~~~
melling
China has 19,000 miles of high-speed rail, with a lot more on the way.

If they use the technology, they’ll be saving billions of riders many hours a
year.

~~~
AFascistWorld
No it does not work like that, not everybody needs and can afford top speed,
rails and trains and the wear and tear cost significantly more. Even in China
only a few popular routes and during holidays have high attendance rates, the
Shanghai-Beijing route has a profit of around 1 billion usd and is considered
big news, most routes struggle to pay interest.

According to China Railway, from 300 km/h to 350 km/h will increase resistance
by 40%, power consumption by more than 50%.

China already has trains with similar speed.

[https://en.wikipedia.org/wiki/Fuxing_(train)](https://en.wikipedia.org/wiki/Fuxing_\(train\))

~~~
melling
2 billion rides a year. That’s an efficient way to move that many people.
Better than cars and jets.

[https://en.m.wikipedia.org/wiki/High-
speed_rail_in_China](https://en.m.wikipedia.org/wiki/High-speed_rail_in_China)

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snvzz
I find annoying that title states mph instead of 360kph, not just because kph
is the correct unit, but because Japan uses kph, too.

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IronBacon
Not to be that guy, but kph doesn't look more correct, km/h it's the SI
defined unit, or maybe kmph.

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esoterica
The SI unit is meters per second, not km/h.

~~~
the8472
power of ten prefixes are part of the SI

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elamje
I don’t understand why a Hyperloop is the next logical step. Making a low
pressure tube is probably pretty hard at scale.

Every design is trying to minimize air resistance. Why not wrap already
existing high speed rail lines with a cheap air barrier then create a wind
tunnel inside rather than a vacuum? If you could move air at a similar speed
to the train you could achieve wind resistance that is effectively negligible
or even negative.

Am I thinking about this wrong? Is the energy required to remove all air from
a tube significantly lower than pushing air through the tube while a train
moves?

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AlbertoGP
I guess that the air resistance against the air barrier would be even higher:
if the air is moving at the speed of the train, you have the same friction per
surface unit than you would have with static air against the moving train,
only your area is now much bigger.

You do save the energy needed to part the air aside as the train moves
forward, since the air barrier would have a constant cross-section. I don’t
know how that compares to the increase in friction due to greater surface.

Finally, other aspect I just realized: when you try to stop the train, you
have a rush of air pushing you at several hundred Km/h, and that would be an
enormous mass. You could enter a side branch which would then close behind the
train and have a smaller mass of air to slow down.

I’m not an engineer and have no experience on the subject, but my hunch is
that it could easily end up being even more difficult.

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dear
Why the US has no high speed rail?

[https://www.youtube.com/watch?v=Qaf6baEu0_w](https://www.youtube.com/watch?v=Qaf6baEu0_w)

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AFascistWorld
The question is, will it have a sustainable operating cost.

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petee
What an ugly train -- when form has no [apparent] function. Considering there
are more naturally shaped vehicles traveling far faster, I'm curious why they
decided to go with the Goofy/Platypus look

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innocenat
Noise reduction. Platypus shape make two smaller tunnel booms instead of one
big boom.

~~~
bpatel576
I don't even care what it looks like. When I see a nation investing in high
speed rail, it makes me frustrated that we are lagging so far behind with
transportation.

~~~
tomohawk
For distances in US, what we have is already superior. Unfortunately, TSA
security theater adds major delays, as does antiquated FAA air traffic control
procedures. Major improvements could be had if we could get government out of
the way and allow innovation.

Moving to high speed rail would also raise the profile of rail, and likely
make it a stronger target of TSA, so you'd likely have the TSA induced delays
for it just like for flying.

High speed rail might make sense on east coast (NY to DC is about 230 miles),
but you'd never get the rights of way to lay the kind of track you'd need to
approach 200 mph. They gave up on expanding the interstate system in this area
many years ago for this reason.

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wbl
Trains can't crash into buildings: the TSA does not make delays for the hell
of it.

~~~
sneak
Considering that the TSA misses more than two thirds of weapons passing
through their checkpoints (they have improved - it used to be 95%), we can
safely say that TSA does indeed make delays for the hell of it. They are not
increasing air safety in any meaningful capacity.

[https://www.forbes.com/sites/michaelgoldstein/2017/11/09/tsa...](https://www.forbes.com/sites/michaelgoldstein/2017/11/09/tsa-
misses-70-of-fake-weapons-but-thats-an-improvement/)

~~~
cheerlessbog
To be fair they don't need to find them all just enough to deter.

~~~
sneak
That’s not accurate. If two people carry weapons onto planes and one gets
caught and the other hijacks the plane and flies it into a building, well -
the TSA has failed in their task.

The sole reason this hasn’t happened in a while is that nobody is really
making any efforts to mass murder with airplanes, TSA or no TSA.

We should probably just shut it down and save the money at this point.

