CHINA | High Speed Rail

[Papagei]

Originally Posted by makita09

Papagei - Whilst the crux of your argument makes sense, the resolution of the equation is alittle bit funny. Stress on the various components increases exponentially with speed, with the main base factor being weight. I don't get how you surmise the one-tenth bit - if you could rephrase that because I dont understand precisely.

Probabilities would suggest that the statistical failure rate would increase exponentially with speed, all other factors being equal. This would also suggest that this increase in failure rate can be mitigated by adjusting other parameters, such as vehicle weight and changes in suspension design.

It would also suggest that if the maintenance regime was increased the probability of failure can be mitigated this way. Economically sensible is another matter. I would also stress that catastrophic failure is unlikely, as it is with airplanes. Small failures are picked up on before an accident can occur. So it is merely a an economic question, not a safety one.

Now the ICE3 axle weight is 16t, which compares poorly with the new Japanese ones at 11t. There is easily scope for reducing weight, the simplest of all engineering concepts in theory.

All aluminium construction, activation of primary suspension to reduce vibration on wheen and bogie, strengthening and lightening of the bogie design (Bombardier, Alstom and Siemens have gone throguh this process) are all available avenues, and things are going this way.

The Chinese don't have access to better materials than Europe, but it'll be along time before anybody takes full advantage of available materials, in the rail industry that is. It has hitherto been uneconomic to use aluminium everywhere, but this is now even being used for slow commuter train more and more for efficiency and is more viable option because of it - economies of scale.

Yes, we shall see. The Spanish need to wait for the signalling. Perhaps they need to arrange a suitable maintenance regime once the signalling allows it. The Japanese eased away from 360km/h as it was a big step, it pushed the tilting requirements quite a long way as the track is designed for 275km/h, and operationally its quite hard get the best out of it if there are still loads of 275km/h slower trains. The AVG however will be built as planned for 360km/h. I see no reason to doubt that, no concrete reason anyway.

The one tenth bit is just a guess since I didn´t claim to which "lower speed" I was comparing. You also can not say that the time until a wheel breaks down is going down exponantially by speed. This is a very compley issue but I think it is enough if one knows that from a certain point of stress, longterm stability is not given any more despite the fact that the system can bear the stress for several hours. For example in the TGV-Testrun of 573 km/h. Many people believe this can be reproduced in daily service. It only can if you change wheels, axles and overhead wires every day.

This leads to your next point: Yes increase in failure rate can be mitigated by adjusting other parameters, such as vehicle weight and changes in suspension design or an increase in maintenance. I alread mentioned that before.
I would say it is mainly an economic question but also a safety question. If you run 350-400km/h you can compensate the occuring problems by checking very often and replacing parts very often. But you still have the problem that the whole system is always running closer to its limit. So if something beyond normal stress happens, for example a piece of metal on the rail, your system directly breakes down. And as we in general come closer to the point of material failure it is statistically more likely that a part fails within your check interval despite the fact that you check more often. The most extreme example is overload. You can check every 2 seconds, if you are running close to overload every second wheel breaks statistically.

From an economic point of view there are many other factors which keep you away from running 350 or 380 km/h. The rails wear out much faster, the overheadwire wears out faster, energy consumption grows by square, sound pressure level extremely grows. All those factors lead to the experience that current high speed rail systems are most efficient between 250 and 300 km/h. You get more ticket income by increasing speed but there is an optimum beyond which the travel time hardly changes at higher speed but costs explode. This is why we might see 350 km/h in some minor cases of prestige and long distance trips but the majority of high speed connections won´t go beyond 300 km/h. If you really wanna go 400-500 km/h you need a maglev and even maglev doesn´t solve all problems. Maglev doesn´t have a safety or maintenance problem at 500 km/h but energy consumption also for maglev grows at the square of speed.

And what does it mean if AGV is built for 360 km/h? None of the problems I mentioned has been solved by AGV. It simply means that the train is certified and allowed to run 360 km/h. It is still economically not useful and it will stay a curiosity that someone uses the 360 km/h. We don´t need faster trains and all that prestige nonsense. We need more efficient trains at 300 km/h and cheaper rolling stock and infrastructure.

Just a hint: If you compare axle load of japanese trains and european trains, be careful to compare on the same basis. European trains are comparing fully loaded while japanese compare empty trains. Japanese trains are intented to run 20 years while european trains have to run 30 years. In japan, high speed trains are running on dedicated tracks while in europe they are sharing old tracks in bad condition with freight rail. All those factors lead to differences.

[makita09]

Originally Posted by Papagei

The one tenth bit is just a guess since I didn´t claim to which "lower speed" I was comparing. You also can not say that the time until a wheel breaks down is going down exponantially by speed. This is a very compley issue but I think it is enough if one knows that from a certain point of stress, longterm stability is not given any more despite the fact that the system can bear the stress for several hours. For example in the TGV-Testrun of 573 km/h. Many people believe this can be reproduced in daily service. It only can if you change wheels, axles and overhead wires every day.

Yes but there is no point in any system below which performance is assumed as you appear to be suggesting. A TGV that only runs at 160km/h (as the TGVs out of Gare Du L'Est did for years beofre LGV Est was constructed) still need to be checked for stress fractures and fatigue.

I am saying that the probablility of time to failure decreases (or rate of wear increases) inversely proportionally to the exponential increase in speed [all other things being equal].

There are no absolutes in engineering, only in operational detail. Every elkement will be risk assessed and the total system designation will be within the sensible risk cause by the weakest element in the system.

Again I don't quite follow what you mean by checking the wheel every 2 seconds, but the safety issue is such that even if running at higher speeds does increase the likelihood of catastrophic failure at high speeds I suggest that a maintenance regime can be formulated to keep the risk of this the same - after all it could happen on trains that run at only 200km/h and must be factored in on risk assessment.

Yes the economic issue I accept, extra energy consumption and wear is the barrier - the same barrier that engineers faced at 100km/h in the 1850s. Nonethesless it is a real one. New contact bar technology is reducing wear on contact cable, and this area of the industry is moving forward quite rapidly. Rail wear is not moving so fast, nonethelss it is a combination of unsprung weight and suspension stiffness that dictates most of the wear to the railheads and wheels. Whilst not returning the same gains as other areas, advances in wheel latheing maintenance techniques, as well as more rigourous wheel and track geometry regimes, especially using laser guidance for accuracy, are eeking this forward, getting cleaner motion and reducing wear at a given speed.

We don't know what it means that AGV is built for 360km/h, and your opinions about the redundency of the specifications are not enough for me to depart form the recieved wisdom on the matter.

Re axle weights, I will verify later but I believe I'm quoting unladen weights for both. Even still, a fully laden axle weight for a latest 700 series is no more than 14t, with 100 per car and lots of luggage.

[Papagei]

Well you are right, as time goes on technology advances and one day we will be able to run 350-400 km/h in an economically viable manner.

I was just saying doing this with todays technology (which is also the technology China has acesss to) is not useful and not as safe as running slower.

[33Hz]

Originally Posted by Papagei

And what does it mean if AGV is built for 360 km/h? None of the problems I mentioned has been solved by AGV. It simply means that the train is certified and allowed to run 360 km/h. It is still economically not useful and it will stay a curiosity that someone uses the 360 km/h. We don´t need faster trains and all that prestige nonsense. We need more efficient trains at 300 km/h and cheaper rolling stock and infrastructure.

Originally Posted by Papagei

Well you are right, as time goes on technology advances and one day we will be able to run 350-400 km/h in an economically viable manner.

I was just saying doing this with todays technology (which is also the technology China has acesss to) is not useful and not as safe as running slower.

You are contradicting yourself. Alstom has said that AGV is designed from the ground up to offer the energy use and economics of a 300km/h TGV when travelling at 360km/h. It will be able to travel safely at 360km/h on any railway designed originally for 300km/h. That's exactly the "one day" you talk about in the second post.

See more here: http://www.railwaygazette.com/news/s...he-market.html

[makita09]

Originally Posted by 33Hz

AGV...It will be able to travel safely at 360km/h on any railway designed originally for 300km/h.

Alignment and signalling permitting of course. The train might be safe but the passengers may fall over if walking about hitting a 300km/h corner at 360km/h without tilt support.

[makita09]

Originally Posted by Papagei

Well you are right, as time goes on technology advances and one day we will be able to run 350-400 km/h in an economically viable manner.

I was just saying doing this with todays technology (which is also the technology China has acesss to) is not useful and not as safe as running slower.

Well its a general rule of thumb that engineering tends to be at its most efficient at two-thirds to three-quarters of 'the limit'. This is probably no doubt true of the AGV as well, even though it is as energy efficient at 360km/h as a previous gen was at 300km/h. Nonetheless the efficiency at operational speed is the important bit.

[worldrailfan]

HunanChina,

thanks for your scheduale post.

I wonder why this link http://www.chinatraintickets.net/china-trains/
never shows G6xxx trains you are listing?

[altachlo87]

well, china's railways is developing in outrageous speed! within 20years, china will be a leading nation in this field i presume! anyhow, this is absolutely good.

[Papagei]

Originally Posted by 33Hz

You are contradicting yourself. Alstom has said that AGV is designed from the ground up to offer the energy use and economics of a 300km/h TGV when travelling at 360km/h. It will be able to travel safely at 360km/h on any railway designed originally for 300km/h. That's exactly the "one day" you talk about in the second post.

See more here: http://www.railwaygazette.com/news/s...he-market.html

Unfortunately this is not that "one day" I was talking about. If you really wanna go on you need single suspended wheels. But the wheels and Bogies in AGV are of the same technology we already know. Maybe the bogies are slightly more lightweight but they are far away from a "breakthrough".

Just citing your linked article from railwaygazette:

Originally Posted by Railwaygazette

The AGV's trailer bogies are 'more conventional', and wheelsets and axles are similar to those on the TGV Duplex.

As I said, important components are simply beeing pushed harder. This means that the new train needs an increased maintenance regime in this field.

Of course AGV is a great train and it certainly will be more efficient than TGV (which was anything but efficient ) but the claims about higher speed are relatively useless for customers.

[HunanChina]

Originally Posted by worldrailfan

HunanChina,

thanks for your scheduale post.

I wonder why this link http://www.chinatraintickets.net/china-trains/
never shows G6xxx trains you are listing?

You're welcome

It's a latest scheduale(Version 2009.12.28), maybe that link is Version 2009.12.26, they have some different. The Wuhan-Guangzhou line is into commercial service just in a couple of days, some adjustment is necessary.

PS:G6XXX just from Changsha to Guangzhou or from Guangzhou to Changsha.

[HunanChina]

Originally Posted by chornedsnorkack

The definitions are:

"Hard sleeper" - actually it is upholstered. No door between aisle and compartment, and 6 beds in a compartment, 3 on each side. The lower beds are most expensive and upper beds are cheapest.

"Soft sleeper" - compartments have doors, and 4 beds in compartment, 2 on each side. Again upper beds are cheaper.

"Deluxe soft sleeper" - only 2 beds in compartment. But those are lower and upper bed, not 2 beds both lower, On the side opposite of the beds there are chairs or something. Very few trains have these.

But I think that Beijing-Hong Kong trains do have deluxe soft sleeper. Do those stop in Changsha?

Beijing-Hongkong(T98 九龙-北京西) have deluxe soft sleeper? I have no ieda, but I sure it stop in Changsha.
I just know the Z18 from Changsha to Beijing have deluxe soft sleeper(VIP soft sleeper).

[worldrailfan]

HunanChina,

Where do you find that scheduale.The link I sent you will not show G6xxxx those trains even between those 2 cities you are listing.

[HunanChina]

Originally Posted by worldrailfan

HunanChina,

Where do you find that scheduale.The link I sent you will not show G6xxxx those trains even between those 2 cities you are listing.

It's a software(only 690KB and free). You can download it at this website.
http://www.jpskb.com/down.htm

but the website only in Simplified Chinese. If you understand some Chinese, find the first "[本地下载]", then click left button of mouse.

PS:the software can update. if the latest timetable release, you can receive a message.

[HunanChina]

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[Skybean]

Highspeed rail train stalled for 3 hours with over a thousand passengers due to a single cigarette smoked by a passenger.

[HunanChina]

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[HunanChina]

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