Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

China laying tracks for 1,000km/h maglev trains

asiatimes.com

Post reply on HN
Print view View original

301–310 of 503 posts

Re: China laying tracks for 1,000km/h maglev trains

#301

Post by weberc2 »

microcolonel wrote: post #292
turtlecloud wrote: post #278

Earlier quoted context omitted.

yep - once u factor in the TSA body shakedown and traffic to airport, then it about evens out air travel.

> yep - once u factor in the TSA body shakedown and traffic to airport, then it about evens out air travel. That's a problem that will be replicated exactly for boarding a train destined to travel at 278m/s. The consequences for a major security failure on a high speed train are, if anything, more dire than those for even a very large passenger aircraft. An 800,000kg barely-subsonic chain of rigid torpedoes barreling…

I get that it's moving fast, but what's the specific threat model? Terrorists hijack the train and somehow drive it off the tracks? Presumably it's easy enough to secure the "cockpit". They could blow it up, but is that dramatically worse than blowing up a train moving 50 mph (genuine question, I'm not sure about the physics)? Especially as these trains don't carry fuel, I can't imagine a tragedy on the scale of 9/11.

Re: China laying tracks for 1,000km/h maglev trains

#302

Post by nicoburns »

userbinator wrote: post #246
nicoburns wrote: post #143

Earlier quoted context omitted.

> using a car is more pleas sent then sharing a bus or metro with strangers Not when it means you're stuck in a traffic jam. In a big city I'd take decent metro system over a car any day.

I certainly think it's better to be stuck in a traffic jam and sit in your own car than stuck in a traffic jam inside a packed vehicle full of other (sometimes extremely unpleasant) people.

If properly designed, you don't get traffic jams on public transport though. Trains have dedicated tracks, and buses can be given bus lanes.

Re: China laying tracks for 1,000km/h maglev trains

#303

Post by weberc2 »

saagarjha wrote: post #296
microcolonel wrote: post #292

Earlier quoted context omitted.

> yep - once u factor in the TSA body shakedown and traffic to airport, then it about evens out air travel. That's a problem that will be replicated exactly for boarding a train destined to travel at 278m/s. The consequences for a major security failure on a high speed train are, if anything, more dire than those for even a very large passenger aircraft. An 800,000kg barely-subsonic chain of rigid torpedoes barreling…

You can’t really hijack a train to hit a specific building, as you can with a plane.

> You can’t really hijack a train to hit a specific building, as you can with a train.

*as you can with a _plane_

Re: China laying tracks for 1,000km/h maglev trains

#304

Post by beerandt »

beerandt wrote: post #104
saberience wrote: post #28

So, as someone that lived in New York for 6 years and California for 6 years, stories like this are incredibly depressing. The US is the world's largest economy and should be the shining example of amazing infrastructure, high-tech, green cities, and forward thinking policies. California is an especially egregious example in terms of infrastructure investment: If California was a country it would be the world's fifth…

I haven't looked at the particulars for this project, but typically the practical limit of high speed rail is 300-500 miles. Beyond that, it's cheaper and greener to fly. If you aren't concerned with cheap or green, and want to focus on fast... Then high speed rail might be a better option until the TSA is involved.

Even the us high speed rail Association claims efficiency only up to ~1000 mile trips, and this is their own best case marketing claims. And they're fighting for the sub 125mph version using existing ROW.

http://www.ushsr.com/hsr/completesystem.html

This paper shows only about a 3% to 20% improvement in co2 per passenger mile by shifting air traffic to already existing hsr in Europe (200-800km trips, taking into account embedded energy, and assuming %50 will be recyclable, which I think is quite optimistic)

https://doi.org/10.1155/2018/6205714

Re: China laying tracks for 1,000km/h maglev trains

#305

Post by yourbandsucks »

sandworm101 wrote: post #294
yourbandsucks wrote: post #277

Earlier quoted context omitted.

6h vs 18h for a trip are two different universes. Sleeper trains are cool and all but a shorter ride is better.

It is time but also energy. At 1000kph a train (at sea level) has massively more drag than an a380 at altitude. Even on electric, these things may have a greater carbon and financial cost than proponants want to admit.

Gonna have to ask you for a cite on that one. Climbing costs energy, as does lift. Piston engines and electric both get better mileage than turbines.

I could see it for a 13 hour flight, maybe. Train tracks don't cross the Pacific, though.

Re: China laying tracks for 1,000km/h maglev trains

#306

Post by saagarjha »

userbinator wrote: post #246
nicoburns wrote: post #143

Earlier quoted context omitted.

> using a car is more pleas sent then sharing a bus or metro with strangers Not when it means you're stuck in a traffic jam. In a big city I'd take decent metro system over a car any day.

I certainly think it's better to be stuck in a traffic jam and sit in your own car than stuck in a traffic jam inside a packed vehicle full of other (sometimes extremely unpleasant) people.

But you can do something else if you’re not driving.

Re: China laying tracks for 1,000km/h maglev trains

#307

Post by breakerbox »

usrusr wrote: post #160
NamTaf wrote: post #82

I’m not sure if it’s just lost in translation, but Wuhan to Guangzhou isn’t even 1000 km so I don’t know where they get the 2200 km they’re quoting. That’s likely a figure for GZ to Beijing. I have used the high speed line between Wuhan and GZ (and through to HK) several times. It’s currently a 4.5 hour direct journey (once per day) or a 5 hour journey if you change at GZ or Shenzhen. The HSR is 300ish km/h at the mo…

> only to stop 4-5 times along the way That's the big one. What HSR needs is not even higher top speed but some control breakthrough that allows much higher train frequencies in order to cut down on stops via more trains that can serve more specialized connections (e.g. the local/through etc). No idea what that breakthrough might be, perhaps something as crazy as rocket-assisted emergency braking.

To be honest, I think wind resistance would play a lot bigger factor than people give it credit for since its force scales nonlinearly with velocity.

At 1000 or even just 600 km/h, wind resistance would do some damage just by letting off the accelerator.

Re: China laying tracks for 1,000km/h maglev trains

#308

Post by gwright »

usaar333 wrote: post #263
nikofeyn wrote: post #183

Earlier quoted context omitted.

> A major problem with train systems in the United States (and this is both short and long haul) is that almost the entire country is sprawl - built around the automobile. this is an excuse i have repeated myself, but it is just that, an excuse. have you actually been to china? i have never seen such sprawl. shanghai is massive and sprawling. but yet, they (china) have extremely efficient and unbelievably cheap train…

Been to China many times actually. I wouldn't call Shanghai sprawl in the American sense. Yes it is huge, but what matters is that driving isn't a quick way to get around the city (there are no quick ways to get around the city, just like NYC) so you don't end up needing a car to live or travel. Agreed though that the Acela cooridor is the most reasonable place for the US to invest in high speed rail

I commute by train to New Haven on the same tracks that Acela uses.

The existing track corridor in New England is not appropriate for true high-speed train service. That really requires new right-of-ways, which would be extremely expensive in the Northeast.

There are currently plans for the next version of Acela but it is more about replacing aging equipment than any true speed upgrade. The Acela trains are almost 20 years old but I've never been on one as the price difference from the regular service isn't worth the small increase in time. Here are some numbers. I'm showing the cheapest "Saver" fares which are limited, must be purchased in advance, and have strict refund rules. I just picked November 4 as the date for advanced purchase (about +30 days):

NYC to Washington DC.

    Acela Non-Stop: $137, 2h37m
    Acela Regular:  $137, 2h57m (+20m from non-stop)
    NorthEast Reg:  $54,  3h25m (+48m from non-stop)
Here are Boston to D.C:

    Acela Non-Stop: $144, 6h39m
    Acela Regular:  $144, 7h5m  (+21m from non-stop)
    NorthEast Reg:  $81,  7h59m (+1h20m from non-stop)
Everyone swooning over the train infrastructure in China seems to overlook the raw power that the Chinese government wields to claim right-of-ways, fix labor rates, and so on. It is also almost impossible get a good sense of the financial structure of those projects. How much money was put into them? Could that money have been better spent elsewhere? What is the debt structure? The ROE? The environmental impact?

Re: China laying tracks for 1,000km/h maglev trains

#309

Post by gorgoiler »

The benefits of projects like this always seem to quote how massive distances can be covered in a few hours. In this case it’s a 2200km journey being done in 2 hours.

That is of course amazing, but doesn’t seem very impactful to boring people like me. I’d be much more excited about my 30 mile train journey being over in 5 minutes instead of 45.

Even that seems selfish. Wouldn’t it be more exciting to have trains that carried 10x as many passengers, reducing fares by massive amounts?

Who is pushing for raw speed over throughput?

Re: China laying tracks for 1,000km/h maglev trains

#310

Post by saagarjha »

kevin_thibedeau wrote: post #168
simion314 wrote: post #128

Earlier quoted context omitted.

Maybe it could cost 50$ and take 2 hours, some people would appreciate having the choice.

But there's a work crew on the tracks so make the trip four hours instead.

It’s still significantly better than driving.
Post reply on HN