
The limits of high-speed rail - bookofjoe
https://mappingignorance.org/2020/01/22/the-limits-of-high-speed-rail/
======
niftich
A richly detailed article that delves into the French TGV speed record, the
extra modifications they applied to what was already a high-speed system, and
the lesser-known physical phenomena that set a performance envelope for this
mode of traction.

Then, in a switch of tone and pacing, admits that profitability potential is
likely most important of them all.

This is why networks -- rather than just individual lines -- are critically
important. High-speed rail works best when it connects robust local
transportation networks that already exist: between cities that they
themselves have robust temporal and spatial transport coverage. It works best
when faraway cities can be brought within commuting range, or further leisure
destinations within daytrip range. Similarly, it works best when it extends
the catchment area of an airport, rather than a service positioned to compete
against point-to-point flights.

But major infrastructure projects often suffer from messy political and public
relations approaches that play up the project's impressiveness and prestige in
isolation, while neglecting to emphasize or champion synergistic improvements
to other parts of the network. Frequent and punctual "normal-speed" rail isn't
as politically energizing, and local transit networks that serve the specific
transport needs of a town are hardly exciting to regional audience, but
without it, high-speed rail is just an expensive showpiece that doesn't serve
a genuinely identifiable transport need. This is a risk with the California
HSR as much as it is with ambitious efforts to bring western Europe's
successful high-speed services further into the EU's east.

~~~
kortilla
People still use airports all of the time for regional flights despite the
airports having crap local connectivity. The California HSR can still be
incredibly successful if it’s as easy to get to as the local airports
(including the public transit poor SJC).

What will kill it is terminating in places not even convenient enough for an
airport location.

~~~
nixass
People IN THE US still use regional flights because all sorts of public
transport in the US are literally third world crap. EU and parts of developed
Asia use a lot of inter-city trains.

Munich<>Frankfurt (400km) is 3 hours with ICE, much less than going to the
airport, wait for check in, boarding, flight, off the plane and to the city
centre. It's around 110e too for returns

~~~
bluGill
A country in the EU and a state in the US are equivalent (for discussion on
transport - in other contexts there are significant differences). Nobody flies
between cities in one state, just like nobody flies between cities in one EU
country. When going to a different country things change - the distances are
now large enough that you fly because it is faster.

Remember, Chicago to New York City is almost the same distance as Munich to
Moscow! (Note that rail advocates will tell you that Chicago to NYC is just
barely in high speed rail range, anything farther even rail advocates don't
pretend to be competitive. Chicago to New York City is not very far on the
scale of the US, so of course we fly.

Yes I will agree that our rail system in the US isn't great, but flying
doesn't compete with the rail system, driving does. A good rail system in the
US would only negatively affect some short flying routes, it would however
mean less people drove.

~~~
richk449
> Nobody flies between cities in one state

The second most popular route in the US is LA to SF.

~~~
jandrese
LA to SF would be an excellent route for HSR, but sadly modern politics and
entrenched land interests make this incredibly difficult.

~~~
alexhutcheson
There are two sets of huge mountains in the way:
[https://en.wikipedia.org/wiki/California_Coast_Ranges](https://en.wikipedia.org/wiki/California_Coast_Ranges)

That's the core issue. CHSRA never had a credible funded plan for building
_either_ crossing, and instead chose to tackle the easy part in the Central
Valley first. Unfortunately, HSR in the Central Valley is effectively useless
without a mountain crossing at at least one end.

~~~
jandrese
Giant mountain ranges didn't stop the Shinkansen.

~~~
magduf
Japan doesn't have the utterly broken politics and lack of interest in
building infrastructure that the USA has.

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princekolt
The article is great but it fails to address another main issue with high-
speed rail in many locations: Having to network with slower traffic.

I recently took a 9.5h train trip from Berlin to Switzerland, and although the
train does travel at the top speed of the section at several locations, we
never reached the top speed of the train set (280km/h), and lots of times we
were travelling at under 100km/h for switching tracks or whatever else. I
didn't log it, but I'd guess we spent less than 50% of the travel time over
200km/h.

That's where Japan's Shinkansen was so groundbreaking. Sure, they also used
this opportunity to migrate from a smaller gauge, but the decision to build a
new network from scratch that doesn't interact with other networks at all paid
off tenfold over the decades as trains started getting faster and faster.

~~~
cameldrv
That's true, but the lower speeds in Germany are also what makes it possible
to drop you right in the city center. The TGV approach is to make straight
lines, and that means for smaller cities, you get dropped off somewhere out in
the country outside the city.

If you've got a comfortable seat, wi-fi, power, and a dining car, spending a
few extra hours on the train is not so bad. It beats spending that same time
on a metro or regional train with a bunch of luggage. It most definitely beats
spending the time going through airport security, walking a kilometer through
a giant shopping mall with gates, waiting in a departure lounge, or waiting at
baggage claim.

That said, there are reasons for each country's choices. France is much less
dense than Germany, so acquiring land to make those straight lines is more
feasible. France also has its population concentrated more in bigger cities
rather than a lot of smaller ones like Germany, so as long as the TGV goes
directly into the bigger cities, most people are happy. Japan is long and
skinny, so average trip distances are longer and the speed is more important.
Japan also has a big infrastructure budget to prop up the economy, so making
straight lines that require loads of tunnels and bridges is not as much of a
problem.

~~~
masklinn
TGV works just fine on regular lines, and uses them when approaching most
cities. In fact classic lines is where most tgv accidents happened. It gets
dedicated high-speed lines for the main legs.

Most TGV will stop at city center train stations, if they don’t and drop you
in the countryside it’s often for political or demographic reasons, or
possibly because the rail lines were _really_ unsuitable (iirc even at low
speed tgv is somewhat limited in its ability to bend).

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throwaheyy
The most limiting factor is the pantograph/catenery contact; as speeds go up
the wire has to be kept at a higher and higher tension to prevent the train
catching up to the standing wave it creates in the wire. If the tension is not
high enough to prevent this, the train will lose electrical contact or even
rip down the wire. This is also why high speed trains can only have one or two
pantographs to collect power.

~~~
ginko
I guess it'd be a big safety headache but perhaps the train could be powered
through the rails? To avoid accidents the rails could be split into sections
that only get powered when a train is directly above them.

~~~
adrianN
Changing the current system would be prohibitively expensive. I also imagine
that you have pretty bad losses at 25kV AC if your conductors are touching the
ground and are potentially wet or covered by snow. It would also be a fire
hazard I guess.

~~~
jandrese
Plenty of metro rail systems use a third rail today, even outside. Maybe their
losses are more manageable because their systems are relatively short compared
to long distance rail, but it doesn't seem like an insurmountable obstacle.

~~~
adrianN
Metro rail runs at a much lower voltage afaik.

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xt00
While air transport has dramatic challenges to switch to non fossil fuels, if
we created vast high speed rail networks we could focus air traffic on the
longer distance flights. As the human race approaches peak population (at
least for a while) we should figure out what the long term infrastructure
should be. Like next 500 years. Once we start branching out to the
stars/galaxy, population will start increasing again.

~~~
ars
> to switch to non fossil fuels

There's no real reason to switch so long as we are using these fuels for
anything else. Let air transport be the very last things changed over, we have
a ton of much lower hanging fruit that we can work on first.

~~~
dragonelite
Heard that the cargo ship fleet is a big contributor to greenhouse gasses.

~~~
dsfyu404ed
It's large overall but tiny per amount of cargo moved a distance.

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micheljansen
This article sent me down the rabbit hole reading about the current state of
the art – the recordholding L0 series. This eliminates the limiting factor
that is the pantograph and instead gets its power through induction:
[https://en.wikipedia.org/wiki/L0_Series](https://en.wikipedia.org/wiki/L0_Series)

~~~
m4rtink
And a first line using this technology is also already being built! :-)
[https://en.m.wikipedia.org/wiki/Ch%C5%AB%C5%8D_Shinkansen](https://en.m.wikipedia.org/wiki/Ch%C5%AB%C5%8D_Shinkansen)

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gorgoiler
The first thing that springs to mind is how amazing smooth the rails were in
the V150 test. The lines I use the most, here in the UK, are way too bumpy and
that’s at a mere 70mph. I understand the legacy of the rail network but it
would be embarrassing to get to the 22nd century without any improvement.

On that note, for the price of HS2, I’d rather see:

1/ smoother tracks

2/ a strong, unified, national brand

3/ dead simple smart phone ticketing

4/ tickets checked when you get off the train, not on

5/ tickets purchasable on the train you are actually on, lower prices, and an
end to the railcard / discount / split ticket confusopoly

6/ simpler utilitarian rolling stock, again with unified branding, no adverts,
and simple monochromatic signing and buttons all following a unified design
language

Perhaps a simpler list though would be:

1/ fire everyone

2/ hire from scratch and completely rethink the rail network in terms of being
100% focused on the passenger, instead of an internal market of contracts
between infrastructure, train operators, and unions.

(“Simpler”!)

~~~
masklinn
> The first thing that springs to mind is how amazing smooth the rails were in
> the V150 test.

High speed lines are necessarily extremely smooth and with very small
tolerances.

French lines come out the factory in rail pieces 200 to 400 meters long and
are thermite-welded together after adjustment. They have no expansion joints
except around bridges (and even then not necessarily)

~~~
jandrese
So how do they handle thermal expansion? Just let the whole system build up
huge pressures in the summer? Special alloys that don't expand so much in the
heat?

~~~
labcomputer
I learned recently that rail (especially continuously welded rail) is
generally kept under tension (I don't understand how it is secured at the end
of the line, though). So when it heats up in the summer, it is simply under
less tension.

Unless it heats up too much, and then it buckles and you get derailments.

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transfire
Meanwhile, the sad situation in the States...

Lobbiests for commercial interests who are potentially undermined by effective
rail have long managed legal strangleholds on significantly improved rail
infrastructure.

A glaring case in point, all passenger rails connecting East and West must go
through Chicago -- far north of southern states. (There is one claimed
southern line, but it never appears to be available for transport.)

Worse still, the Republican party has bamboozled their members into actually
believing trains are not cost effective and therefore just a give-away to the
undeserving lazy jobless welfare recipients who use them, because they can't
afford cars.

Yes, it's that fracked up here.

~~~
jcranmer
> A glaring case in point, all passenger rails connecting East and West must
> go through Chicago -- far north of southern states. (There is one claimed
> southern line, but it never appears to be available for transport.)

This is a matter of geography. Your main eastern market is the DC-Boston
corridor--as populated as all of the other states on the Atlantic seaboard
combined. So that means that you're mostly looking at terminating there, no
matter where on the West Coast you originate. If you start in the Northwest,
you have to cross south of Lake Michigan to reach the NEC, so Chicago is en
route. If you're in Northern California, you'll emerge from the Front Range
near Denver, and you can pick whichever hub you want--might as well pick the
one everyone else is using and choose Chicago. Even as far south as Oklahoma
City, going to DC via Chicago only adds 100-200 miles to your route. It's not
until you get to Dallas that reaching the NEC via Atlanta/Charlotte/Raleigh-
Durham makes sense.

Historically, by the latter half of the 1800s, the railroad industry already
settled on using Chicago as the main termination of every major railroad, and
thus the major transshipment point. Geographically, the logical point is
bounded by the southern tip of Lake Michigan and northern bank of the Ohio
River (as you have prairies to the north and hills to the south). In
principle, a city like St. Louis or Indianapolis could have grown up to be the
major transshipment hub instead of Chicago, but you'd still be complaining
about the lack of southern East-West lines in that scenario.

------
wyxuan
tl;dr HSR can go up to 570 kmh as evidenced by French testing, but limitations
such as the wheel, power delivery from the overhead lines, and changes to the
track mean that meeting or exceeding this limit would be very difficult.

~~~
simula67
Magnetic Levitation can exceed this speed limit. From the FTA:

> a Japanese maglev had set a speed record at 581 km/h. The French managers
> considered it pointless as well as prudent to force the experiment to exceed
> that speed, as they could have entered a kind of “international race” that
> they did not have much chance of winning. Time would prove them right: in
> 2015, another L0 series maglev reached 603 km/h on the Yamanashi test line.

Chinese maglev seems to run at 431 km/h and brings in losses of more than 1
billion RMBs[1]. So these trains may not be economical.

[1]
[https://en.wikipedia.org/wiki/Shanghai_maglev_train](https://en.wikipedia.org/wiki/Shanghai_maglev_train)

~~~
seanmcdirmid
The Chinese maglev is just impractical: it doesn’t go into the city and it’s
quicker and about as cheap to just take a cab to the airport.

The Japanese maglev is going to be a full blown commuter alternative to the
massively successful tokaido Shinkansen.

~~~
melling
China is also build new low-speed maglevs:

[https://www.cnn.com/travel/article/china-driverless-
maglev-t...](https://www.cnn.com/travel/article/china-driverless-maglev-
trains/index.html)

There are many places where 100 mph is sufficiently fast.

~~~
seanmcdirmid
The Changsha HSR-airport maglev is actually useful, but is very much a local
transit option. It still doesn’t go into the city, but I’ve had to make that
connection before. The Shanghai maglev doesn’t connect to anything more than a
subway station.

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ngcc_hk
Great. In general it is a great acheivement as a lot of people can move a lot
quicker cheaper and easier. Going through airline ...

But as china situation unfold, the arrangement of such ease to connect has a
price to pay. Even airline would have the same issue one may say. But in 2003
when sars did it’s tolls it is mainly via airplane and slow train.

The speed one held the current chaos. No one can stop progress. But are all
progress great. Wonder.

Some just minor but important barrier. The join border of the high speed
between hk and china meant when the case is found (or at least high temp
symptom) instead of sending the patient or blocking him, he comes the index
patient in.

