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Post by rubbertoe on Oct 26, 2010 10:22:22 GMT -8
Newly opened high speed line hits 420kph in trail run. In service speed a more modest 350kph (thats 217mph). Modest indeed. Good to see they are doing something productive with all the money we are pouring into their country. Putting hundreds of thousands of people to work, and building the worlds largest high speed rail network that will be around for a very long time. Now, why didn't we think of that...
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Post by jdrcrasher on Oct 26, 2010 15:53:37 GMT -8
And just think: They're already planning 1000 KPH technology... MAN, WE'RE GETTING SO FAR BEHIND!!!!
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Post by Gokhan on Oct 26, 2010 15:57:13 GMT -8
And just think: They're already planning 500-1000 MPH corridors. Umm... How do they plan to deal with the shock waves and breaking the sound barrier (770 MPH)?
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Post by jdrcrasher on Oct 26, 2010 16:00:42 GMT -8
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Post by Gokhan on Oct 26, 2010 16:09:47 GMT -8
Yes, I thought so. The speed of sound is 1240 km/h. Commercial airliners fly around 900 km/h in thin atmosphere. 1000 km/h for a train would be very difficult due to intense air friction and heating. I heard about dreams of vacuum tunnels. With a vacuum tunnel, it could be done but I doubt it could be cost-effective. Besides it could be very dangerous if there is a vacuum leak. I would guess they would set the air pressure around the same level as at 40,000-ft altitude, not an actual vacuum, which would be super dangerous.
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Post by Gokhan on Oct 26, 2010 16:46:36 GMT -8
Yes, I thought so. The speed of sound is 1240 km/h. Commercial airliners fly around 900 km/h in thin atmosphere. 1000 km/h for a train would be very difficult due to intense air friction and heating. I heard about dreams of vacuum tunnels. With a vacuum tunnel, it could be done but I doubt it could be cost-effective. Besides it could be very dangerous if there is a vacuum leak. I would guess they would set the air pressure around the same level as at 40,000-ft altitude, not an actual vacuum, which would be super dangerous. I should also strongly emphasize that higher speeds make no difference for lines with mile-apart or similarly spaced stations. Red Line to North Hollywood wouldn't go there much quicker if it could reach 1000 km/h. The reason is the 3 MPH/s public-transit limit on the acceleration and deceleration and station dwells. People overlook this simple fact and think that maglev and high-speed rail will benefit urban transit lines. Are they going to actually build a 400-mile-long vacuum tunnel? There is simply no way. Therefore, I think this whole 1000 km/h business is nothing but a political ploy by the government of China to claim that they are very powerful.
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Post by jdrcrasher on Oct 28, 2010 6:38:30 GMT -8
Ummm..... "There is simply no way" You obviously haven't remembered that this is China, not the United States. They built the Great Wall.....and they're currently building a few Manhattan's worth of high-rises EVERY YEAR.....
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Post by Gokhan on Oct 28, 2010 9:30:24 GMT -8
Ummm..... "There is simply no way" You obviously haven't remembered that this is China, not the United States. They built the Great Wall.....and they're currently building a few Manhattan's worth of high-rises EVERY YEAR..... Actually building high-rises is quite straightforward. China is currently No. 1 and Turkey is No. 2 in the world on that. But that doesn't mean they are going to spend $100 billion on a tunnel. As I said, it would have negligible benefits over regular high-speed rail and therefore wouldn't be economically justified. If they build a-few-mile-long tunnel for demonstration or show-off purposes, it's a different story.
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Post by James Fujita on Oct 28, 2010 10:31:59 GMT -8
No matter what the technology is, there's a limit to the acceleration which a human being can take. Human beings weren't designed for sudden starts or stops.
That, more than anything, will limit the practical applications of ultra-fast urban transit.
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