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Old March 20th, 2015, 05:43 PM   #1561
M-NL
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Quote:
Originally Posted by loefet View Post
There is no other high speed train that accelerates as a N700 train
I would be interested to see a direct comparison between the AGV, ICE3 (403), ICE (407), the E5 and the N700. I have a feeling the differences might be smaller then you would expect.
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Old March 20th, 2015, 06:21 PM   #1562
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Quote:
Originally Posted by M-NL View Post
I would be interested to see a direct comparison between the AGV, ICE3 (403), ICE (407), the E5 and the N700. I have a feeling the differences might be smaller then you would expect.
This has been debated numbers of time.
Alstrom has not disclosed any of the data in terms of acceleration rate.
Rule of thumb is less amount of load per powered axle the faster the acceleration rate.

As for TGV able to run in 3~4 minutes intervals, sorry but it must be a very special case in which they cover a very short distance before the separate destination or it involves only two train sets since TGV are notoriously slow in acceleration and deceleration which can be easily be calculated by timing how much time it takes to reach 50Km from stand still. This makes it impossible to run the trains on short intervals since it will not have enough distance to stop in case of an emergency.
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Old March 20th, 2015, 08:22 PM   #1563
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Quote:
Originally Posted by M-NL View Post
I would be interested to see a direct comparison between the AGV, ICE3 (403), ICE (407), the E5 and the N700. I have a feeling the differences might be smaller then you would expect.
Count Chinese CRH380AL in as well, it's a heavily upgraded E2 with some European technology, 14m2t, 20440kw, light axle load, can be comparable to N700, can reach 300km/h in just over 4mins and within 12.5km distance.
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Old March 20th, 2015, 10:02 PM   #1564
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Quote:
Originally Posted by Maarten Otto View Post
Your laws of physics are flawed and here is why:

If all trains accelerate and decelerate the same way, capacity is not effected.

Site note: They do run in 3 to 4 minute intervals on some parts of the LGV lines in certain situations.
Sure they can go that close no problems, as long as all train accelerates the same way. The problem though comparing the TGV system with the Shinkansen is that the complexity of the service in the Shinkansen, with different stopping patterns along with a very busy line then using a slower accelerating train, would hurt the capacity of the line. As far as I know then the TGV services as pretty similar along a line, and the number of stops are way less than what you find on a Shinkansen line, making the acceleration number less important.

Quote:
Originally Posted by M-NL View Post
I would be interested to see a direct comparison between the AGV, ICE3 (403), ICE (407), the E5 and the N700. I have a feeling the differences might be smaller then you would expect.
There was a discussion on high speed train accelerations a while back. And from that I can only draw one conclusion, all manufacturer specifies the numbers in different ways so you can't really compare, but one thing is certain, an full EMU does better than any with power units at the end.
http://www.skyscrapercity.com/showthread.php?t=988649

The one numbers that I really can give you a comparison of is between N700 and E5, and in that case then the N700 accelerates about 50% faster than the E5 (2.6 km/h/s / 1.71 km/h/s = 1.5 times).

Quote:
Originally Posted by voyager221 View Post
Count Chinese CRH380AL in as well, it's a heavily upgraded E2 with some European technology, 14m2t, 20440kw, light axle load, can be comparable to N700, can reach 300km/h in just over 4mins and within 12.5km distance.
I'm not so sure that it can beat the N700, since it reaches 270 km/h in just 3 minutes. Sure the acceleration is slower at higher speed but it's still massively fast.
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Old March 20th, 2015, 11:48 PM   #1565
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Quote:
Originally Posted by loefet View Post


I'm not so sure that it can beat the N700, since it reaches 270 km/h in just 3 minutes. Sure the acceleration is slower at higher speed but it's still massively fast.
It can't, as the N700 is still the benchmark for the fastest accelerating HSR set, worldwide.
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Old March 21st, 2015, 02:02 AM   #1566
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Quote:
Originally Posted by loefet View Post
I'm not so sure that it can beat the N700, since it reaches 270 km/h in just 3 minutes. Sure the acceleration is slower at higher speed but it's still massively fast.
Could the different top speed play a bit role here?
Since CRH380AL is designed to reach 380km/h on a small grade, so the torque of the motor is used evenly across all speed up to 380km/h?
N700 has no need to run at over 300km/h and also put emphasis on reaching 300km/h as quick as possible, so different tuning or control of motor has been used?
It's not like N700 is using some secrect technology, so when it can do something others can't, maybe it has given up some features others need.
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Old March 21st, 2015, 03:55 AM   #1567
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JAPAN | High Speed Rail

I've always wondered about that. I had always read that in real world application the n700 has the fastest acceleration of all the trainsets in part due to weight distribution and distributed power. It would be interesting to see the AGV, for example, compared.

I'd also be curious to know what is so different about TGV track layout and procedure that is doesn't accelerate at full speed. Acceleration has a big bearing on actual service time and as a result on revenue, one would think.

Unfortunately what most people care about is top speed, and not how fast you get to that speed.
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Old March 21st, 2015, 04:15 AM   #1568
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Originally Posted by loefet View Post
Sure they can go that close no problems, as long as all train accelerates the same way.
Sorry but no they can't since the TGV can't reach minimum safe distance between trains within 3 minutes. That is the problem with low acceleration rate.
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Old March 21st, 2015, 04:59 AM   #1569
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JAPAN | High Speed Rail

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Originally Posted by SamuraiBlue View Post
Sorry but no they can't since the TGV can't reach minimum safe distance between trains within 3 minutes. That is the problem with low acceleration rate.

Isn't deceleration rate more important than acceleration? I don't see why acceleration matters if all trains are similar.

If they're using a moving block system and assuming trainsets are all similar then the safe distance increases as speeds go up. So, for example a train going 200km/h would have a much smaller block than one going 300km/h.

I know Japan uses the moving block system and newer transit systems do too.

As for the AGV not publishing stats on acceleration I would assume that is intentional. The n700 is well known for its acceleration rate. It is also quite lightweight meaning it can stop more quickly.

I think the comparison between the e5 and n700 is most telling. Two Japanese trains with different needs. And the needs have less to do with stopping patterns. Scheduling does play a role, but the main reason fast acceleration is needed on the Tokaido line is because stations are so close together. This is less important on the Tohoku line.

European stations are generally not as close to each other as Japanese ones along the Tokaido. If you can't get up to max speed quickly then there is little point in trying to go faster. You're just wasting energy if you have to start to decelerate right away. It also helps Kodama and Hikari trains to keep a decent schedule despite making more stops.

Of note the Chuo maglev line will be ~40 minutes to Nagoya direct but the all stops hourly version will increase that to about 100 minutes if I'm not mistaken. That is a huge jump and it has everything to do with stopping and starting (and waiting a bit at stations).

I might spend some time later doing up a matrix based on distances on hyperdia.
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Old March 21st, 2015, 05:14 AM   #1570
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Quote:
Originally Posted by bluemeansgo View Post
Isn't deceleration rate more important than acceleration? I don't see why acceleration matters if all trains are similar.

If they're using a moving block system and assuming trainsets are all similar then the safe distance increases as speeds go up. So, for example a train going 200km/h would have a much smaller block than one going 300km/h.

I know Japan uses the moving block system and newer transit systems do too.
Exactly, the block is to ensure minimum safe distance. The faster the train and/or lower deceleration rate the larger the distance apart trains needs to be and to reach that distance trains at stand still needs time to reach that distance especially when they have slow acceleration. So a train with slower acceleration rate then N700 will naturally need more time to move out of the block of the stand still train for the next train to leave the station.
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Old March 21st, 2015, 05:28 AM   #1571
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Originally Posted by SamuraiBlue View Post
Exactly, the block is to ensure minimum safe distance. The faster the train and/or lower deceleration rate the larger the distance apart trains needs to be and to reach that distance trains at stand still needs time to reach that distance especially when they have slow acceleration. So a train with slower acceleration rate then N700 will naturally need more time to move out of the block of the stand still train for the next train to leave the station.

I'm not sure how the moving block system works for high speed trains but the moving block system I'm familiar with on my local transit system which is automated is of a train at rest in the station is effectively zero. The block size increases based on the speed of the train.

Older systems weren't smart enough to calculate based on speed and blocks were fixed sizes.

I'm fairly certain japan has upgraded its signalling to be able to use variable block sizes. I believe I have seen that somewhere. Not sure about the TGV.
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Old March 21st, 2015, 07:27 AM   #1572
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Quote:
Originally Posted by voyager221 View Post
Could the different top speed play a bit role here?
Since CRH380AL is designed to reach 380km/h on a small grade, so the torque of the motor is used evenly across all speed up to 380km/h?
N700 has no need to run at over 300km/h and also put emphasis on reaching 300km/h as quick as possible, so different tuning or control of motor has been used?
It's not like N700 is using some secrect technology, so when it can do something others can't, maybe it has given up some features others need.
N700 design speed is actually 330 km/h - whether or not that will ever come in to use is up for debate, though there are some parts of the Tokaido line where it's possible.

And it is secret technology, in a sense. All manufacturers that have created their own propulsion systems can claim that they are 'corporate secrets'. They may use broadly similar technologies, but use different approaches and integration of components to achieve different results. These configurations and designs are the secrets that aren't told outside of the company.
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Old March 21st, 2015, 09:31 AM   #1573
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JAPAN | High Speed Rail

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Originally Posted by Sopomon View Post
N700 design speed is actually 330 km/h - whether or not that will ever come in to use is up for debate, though there are some parts of the Tokaido line where it's possible.



And it is secret technology, in a sense. All manufacturers that have created their own propulsion systems can claim that they are 'corporate secrets'. They may use broadly similar technologies, but use different approaches and integration of components to achieve different results. These configurations and designs are the secrets that aren't told outside of the company.

330km/h (205mph) is the top speed proposed for the U.S. High speed line in California using the n700i. Also the privately built Texas HSR will be using n700i should it be built.

I believe there are slight differences but essentially it is the same base tech as the n700/n700a.

As for in Japan I think it has a greater chance of being used along the Sanyo line especially in light of the Chuo line taking center stage and rumours that they may add a station or two to the Tokaido line when the Chuo comes on line.
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Old March 21st, 2015, 10:41 AM   #1574
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Originally Posted by bluemeansgo View Post
I'd also be curious to know what is so different about TGV track layout and procedure that is doesn't accelerate at full speed.
Because TGV has no dedicated tracks on station yards it has to adhere to the local speed limits there, which is just 30 km/h in a lot of cases. Then they use conventional tracks to get to the nearest LGV. In case of Gare du Nord to LGV Nord that's takes about 10 to 15 minutes, again at the local track speed limit.
Shinkansen was designed for trains to be able to speed of at max power. Only exception is Tokyo where there wasn't enough space. Both JR Central and JR East have speeds in the 110 km/h range while inside the Tokyo urban area.

As for procedures: A shinkansen stops exactly where marked and all doors open automatically so all people can prepare themselves at the exact spot they need to be. In case of TGV there is a 10 to 15 meter tolerance and travelers have to open the doors themselves. It's these small things that cause dwelling times to almost double.

Quote:
Originally Posted by bluemeansgo View Post
I'm fairly certain japan has upgraded its signalling to be able to use variable block sizes. I believe I have seen that somewhere. Not sure about the TGV.
TGV still uses fixed block TVM-430, but is eventually going to switch to ETCS L2 or L3. DS-ATC and ATC-NS still use fixed blocks as far as I know, but those blocks are so short that it effectively makes no difference.
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Old March 21st, 2015, 08:43 PM   #1575
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Shinkansen does NOT have particularly good acceleration.
Compare Tokaido Shinkansen with Taiwan High Speed Rail!

Shinkansen:
http://english.jr-central.co.jp/info.../westbound.pdf
First morning Kodama Tokyo-Osaka is 633. Originates Tokyo 6:56, terminates in Osaka 11:00.
Trip time thus 4:04.
It is soon overtaken by Nozomi 203. Originates Tokyo 7:00, terminates in Osaka 9:33.
Trip time thus 2:33 - and it´s not the fastest Nozomi, they do not travel the same duration! First morning Nozomi, 1, originates Tokyo 6:00, and is at Osaka 8:24, thus just 2:24 (and is it arrival or departure?)!

Now, Kodama 633 is thus 91 minutes slower than Nozomi 203, and at least 100 minutes slower than Nozomi 1.
It makes 11 stops than Nozomi skips: 9 between Shin-Yokohama and Nagoya, 2 between Nagoya and Kyoto.
Thus over 8 minutes for stop, and probably over 9 minutes.

Now look at THSR!
http://www5.thsrc.com.tw/en/ticket/t...ate=2015/03/22
All all-stop trains take 2:00.
All express trains take 1:36, and skip 4 stations.
Thus uniformly 6 minutes per stop.
And they DO get passed. Look at 613, originates Taihoku 7:36 and is overtaken by 115 which has originated Taihoku 7:54.

So why are Kodamas so slow?
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Old March 21st, 2015, 09:30 PM   #1576
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What does this have anything to do with acceleration.
And please, it is Taipei not Taihoku
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Old March 21st, 2015, 09:44 PM   #1577
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Then what feature of Tokaido Shinkansen makes the time cost of a stop so big, if not acceleration of the trains?
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Old March 21st, 2015, 09:51 PM   #1578
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Okay, not good acceleration. Got speed profiles? Did you look at stop spacing? Also Tokaido is 515.4 km, Taiwan 345 km. That would explain the train taking 4 hours to travel on an all stop. Average stop distance and max speed also need to be compared. The N700 is probably the most superior vehicle in terms of acceleration and an envy for any HSR. In comparison to Europe HSR, Japan while not having the max speeds has the best acceleration which cuts down on time.
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Old March 21st, 2015, 10:05 PM   #1579
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Quote:
Originally Posted by chornedsnorkack View Post
Shinkansen does NOT have particularly good acceleration.
Compare Tokaido Shinkansen with Taiwan High Speed Rail!

Shinkansen:
http://english.jr-central.co.jp/info.../westbound.pdf
First morning Kodama Tokyo-Osaka is 633. Originates Tokyo 6:56, terminates in Osaka 11:00.
Trip time thus 4:04.
It is soon overtaken by Nozomi 203. Originates Tokyo 7:00, terminates in Osaka 9:33.
Trip time thus 2:33 - and it´s not the fastest Nozomi, they do not travel the same duration! First morning Nozomi, 1, originates Tokyo 6:00, and is at Osaka 8:24, thus just 2:24 (and is it arrival or departure?)!

Now, Kodama 633 is thus 91 minutes slower than Nozomi 203, and at least 100 minutes slower than Nozomi 1.
It makes 11 stops than Nozomi skips: 9 between Shin-Yokohama and Nagoya, 2 between Nagoya and Kyoto.
Thus over 8 minutes for stop, and probably over 9 minutes.

So why are Kodamas so slow?
Since the Tokaido Shinkansen is so busy (in other words, there are so many trains each hour that there are only a few slots available for the Kodamas to fit in the timetable).
On the one Kodama I counted on then I saw that it was passed by 7 Nozomi and 2 Hikari trains on it's journey from Tokyo to Osaka, and some of them are so close together that the Kodama have to wait for both to pass before they get a new gap that is long enough. Which means that if they run with 3 minutes in between the trains then one stop to let one train pass will take 6 minutes, to let two trains past means 9 minutes. And since the Tokaido Shinkansen have so many stations then it soon ad up to those 4 hours.

Note on the other hand that I bet that no-one really takes the Kodama the whole stretch, just to the nearest station that can give you a faster service to get to your destination, since the cost between the different services isn't that great to begin with ($2.6 to be exact between the Kodama and Hikari compared to the Nozomi). So the time don't really matter that much, the Kodamas are there to improve service in those regions.

Quote:
Originally Posted by G5man View Post
The N700 is probably the most superior vehicle in terms of acceleration and an envy for any HSR. In comparison to Europe HSR, Japan while not having the max speeds has the best acceleration which cuts down on time.
Absolutely correct, especially when you have several stops along the route.
Not to forget that they even managed to add space for an additional service/hour thanks the quicker acceleration of the N700.

Last edited by loefet; March 21st, 2015 at 10:12 PM.
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Old March 21st, 2015, 11:09 PM   #1580
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Which means that if they run with 3 minutes in between the trains then one stop to let one train pass will take 6 minutes, to let two trains past means 9 minutes.
But what does a stop take where no trains pass?
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