daily menu » rate the banner | guess the city | one on oneforums map | privacy policy | DMCA | news magazine | posting guidelines

Go Back   SkyscraperCity > Infrastructure and Mobility Forums > Railways

Railways (Inter)national commuter and freight trains



Global Announcement

As a general reminder, please respect others and respect copyrights. Go here to familiarize yourself with our posting policy.


Reply

 
Thread Tools
Old December 10th, 2014, 11:02 PM   #801
Suburbanist
on the road
 
Suburbanist's Avatar
 
Join Date: Dec 2009
Location: the rain capital of Europe
Posts: 27,539
Likes (Received): 21253

How close (time or distance) can two maglev trains travel together on same track and direction at full speed?
__________________
YIMBY - Yes, in my backyard!
Suburbanist no está en línea   Reply With Quote

Sponsored Links
Old December 11th, 2014, 07:33 AM   #802
k.k.jetcar
Registered User
 
k.k.jetcar's Avatar
 
Join Date: Jul 2008
Location: Sapporo
Posts: 1,812
Likes (Received): 452


*conjecture*
The normal off-peak service is 5tph, with 4 trains being non-stop expresses between Tokyo and Nagoya, and one being an all stops service. This makes for 15 minute headways for the express trains, with the all-stops threading between these. Peak services apparently can be run at 7~8 min. headways.

http://kenplatz.nikkeibp.co.jp/artic...24/534916/?P=3
k.k.jetcar no está en línea   Reply With Quote
Old December 11th, 2014, 11:30 AM   #803
chornedsnorkack
Registered User
 
Join Date: Mar 2009
Posts: 4,979
Likes (Received): 388

Quote:
Originally Posted by k.k.jetcar View Post

*conjecture*
The normal off-peak service is 5tph, with 4 trains being non-stop expresses between Tokyo and Nagoya, and one being an all stops service. This makes for 15 minute headways for the express trains, with the all-stops threading between these.
What will be the dwell time in stations where a train is not overtaken, and what will be dwell time in station when a train is overtaken?
chornedsnorkack no está en línea   Reply With Quote
Old December 11th, 2014, 11:35 AM   #804
Suburbanist
on the road
 
Suburbanist's Avatar
 
Join Date: Dec 2009
Location: the rain capital of Europe
Posts: 27,539
Likes (Received): 21253

Ok, these are service plans. What I wanted to know is, from an engineering safety point, what is the minimum distance or interval between two full-speed maglevs.
__________________
YIMBY - Yes, in my backyard!
Suburbanist no está en línea   Reply With Quote
Old December 11th, 2014, 11:50 AM   #805
chornedsnorkack
Registered User
 
Join Date: Mar 2009
Posts: 4,979
Likes (Received): 388

Quote:
Originally Posted by Suburbanist View Post
Ok, these are service plans. What I wanted to know is, from an engineering safety point, what is the minimum distance or interval between two full-speed maglevs.
I think it is technically dictated.
The overtaken train must start to decelerate ahead of points, which causes the headway to diminish as the full speed train pursues. Then the points must be returned to the passage of the full speed train. And then the stopped train can only leave the station after the overtaking train has passed both points. Right?
chornedsnorkack no está en línea   Reply With Quote
Old December 12th, 2014, 07:32 AM   #806
k.k.jetcar
Registered User
 
k.k.jetcar's Avatar
 
Join Date: Jul 2008
Location: Sapporo
Posts: 1,812
Likes (Received): 452

The minimum distance between two vehicles traveling at 500km/h is at least 6km, the distance it takes to stop from that speed using conventional regenerative braking.

Quote:
and what will be dwell time in station when a train is overtaken?
According to the conjectural string diagram in the linked article, the dwell time for the all stops service while being overtaken is around 5 or 6 min.

Terminal turnaround times are 18~20 min, very leisurely given current shinkansen turnaround times.

Last edited by k.k.jetcar; December 12th, 2014 at 07:40 AM.
k.k.jetcar no está en línea   Reply With Quote
Old December 12th, 2014, 11:13 AM   #807
chornedsnorkack
Registered User
 
Join Date: Mar 2009
Posts: 4,979
Likes (Received): 388

Quote:
Originally Posted by k.k.jetcar View Post
According to the conjectural string diagram in the linked article, the dwell time for the all stops service while being overtaken is around 5 or 6 min.
And importantly, it makes these long stops in EVERY station. I count about 72 minutes for the all-stop service... these 4 stops cost 32 minutes, meaning 8 minutes per stop.
chornedsnorkack no está en línea   Reply With Quote
Old December 12th, 2014, 11:23 AM   #808
Suburbanist
on the road
 
Suburbanist's Avatar
 
Join Date: Dec 2009
Location: the rain capital of Europe
Posts: 27,539
Likes (Received): 21253

Quote:
Originally Posted by k.k.jetcar View Post
The minimum distance between two vehicles traveling at 500km/h is at least 6km, the distance it takes to stop from that speed using conventional regenerative braking.
.
Even emergency braking?

Maybe I'm totally wrong, but I'd think that cutting thrust at 500km/h, at sea level, would reduce speed very fast due to aerodynamic drag.
__________________
YIMBY - Yes, in my backyard!
Suburbanist no está en línea   Reply With Quote
Old December 12th, 2014, 11:27 AM   #809
chornedsnorkack
Registered User
 
Join Date: Mar 2009
Posts: 4,979
Likes (Received): 388

Quote:
Originally Posted by Suburbanist View Post
Even emergency braking?

Maybe I'm totally wrong, but I'd think that cutting thrust at 500km/h, at sea level, would reduce speed very fast due to aerodynamic drag.
You are.
Planes land at 300 km/h, not 500... and they need heavy braking to stop in the 3 km of runway.
__________________

JuaanAcosta liked this post
chornedsnorkack no está en línea   Reply With Quote
Old December 12th, 2014, 08:50 PM   #810
bluemeansgo
Registered User
 
bluemeansgo's Avatar
 
Join Date: Oct 2008
Posts: 451
Likes (Received): 124

Quote:
Originally Posted by chornedsnorkack View Post
You are.
Planes land at 300 km/h, not 500... and they need heavy braking to stop in the 3 km of runway.
heavy braking and if I'm not mistaken, reverse thrusters. When you think about it, planes start to decelerate from 900km/h something like 150km away from the airport in most cases.

Last edited by bluemeansgo; December 12th, 2014 at 08:56 PM.
bluemeansgo no está en línea   Reply With Quote
Old December 13th, 2014, 01:03 PM   #811
Suburbanist
on the road
 
Suburbanist's Avatar
 
Join Date: Dec 2009
Location: the rain capital of Europe
Posts: 27,539
Likes (Received): 21253

Quote:
Originally Posted by bluemeansgo View Post
heavy braking and if I'm not mistaken, reverse thrusters. When you think about it, planes start to decelerate from 900km/h something like 150km away from the airport in most cases.
Not a good comparison. Planes do that to minimize fuel consumption. It is possible to stall a plane in a matter of a few seconds. Of course you don't want that!

As for braking distance on the ground, remember that, ailerons notwithstanding, plane are still designed to provide lift. Trains are not. Else, they'd go off tracks!

Current steel wheel-on-rail trains theoretical "take-off" speed are around 800km/h for regular consists (if they could theoretically reach that speed).

Maglevs travel much closer to the ground and wouldn't take off, though they are subject to requirements on vertical curve radii, mostly to avoid "low G" effects that are very uncomfortable for passengers.
__________________
YIMBY - Yes, in my backyard!
Suburbanist no está en línea   Reply With Quote
Old December 13th, 2014, 01:42 PM   #812
Silver Swordsman
Registered User
 
Join Date: Nov 2011
Posts: 371
Likes (Received): 101

Quote:
Originally Posted by Suburbanist View Post

Maglevs travel much closer to the ground and wouldn't take off, though they are subject to requirements on vertical curve radii, mostly to avoid "low G" effects that are very uncomfortable for passengers.
Hahaha, thank you for reminding me of low-G effects on current HSR networks, especially when they have areas that quickly transition from -2.5% to 2.5%. If you pay attention carefully, you can actually feel the train going through a curve or up and down a hill. It won't be enough to make your coffee levitate, but those with sensitive stomachs can be affected.


A "hilly" HSR/maglev can actually make people "trainsick"
__________________
My Virtual-Model Railroad: High Speed Rail in RCT3
Project Anniversary: Click Here
Silver Swordsman no está en línea   Reply With Quote
Old December 13th, 2014, 01:50 PM   #813
Suburbanist
on the road
 
Suburbanist's Avatar
 
Join Date: Dec 2009
Location: the rain capital of Europe
Posts: 27,539
Likes (Received): 21253

Quote:
Originally Posted by Silver Swordsman View Post
Hahaha, thank you for reminding me of low-G effects on current HSR networks, especially when they have areas that quickly transition from -2.5% to 2.5%. If you pay attention carefully, you can actually feel the train going through a curve or up and down a hill. It won't be enough to make your coffee levitate, but those with sensitive stomachs can be affected.


A "hilly" HSR/maglev can actually make people "trainsick"
Yeah, the human body has some strange features. It can deal with fairly high constant (vector) acceleration. It can take some direct hits without anything but a muscular pain for 2 seconds. Yet, put a G inversion and it gets upset (without training). Now if you want to make train passengers sick, you put some tight vertical curves + compensated (like on "pendolino" trains) horizontal curves, and you'd have people feeling really ill , even at relatively low (200-250 km/h) speeds. I imagine what would happen with a 2500m/2000m tight curves (H/V) on a maglev train :p
__________________
YIMBY - Yes, in my backyard!
Suburbanist no está en línea   Reply With Quote
Old December 13th, 2014, 08:50 PM   #814
JuaanAcosta
Juan Acosta
 
JuaanAcosta's Avatar
 
Join Date: Sep 2014
Posts: 190
Likes (Received): 475

I guess that Thyssen-Siemens have studied the effects in human bodies of g-forces at such high speed, I mean, they had working for many years the Emsland test facility but also the Shanghai Transrapid line in China (which is really curvy, taking account of how long the link is). Or at least they should have done it.
JuaanAcosta no está en línea   Reply With Quote
Old December 16th, 2014, 12:59 AM   #815
bluemeansgo
Registered User
 
bluemeansgo's Avatar
 
Join Date: Oct 2008
Posts: 451
Likes (Received): 124

Quote:
Originally Posted by JuaanAcosta View Post
I guess that Thyssen-Siemens have studied the effects in human bodies of g-forces at such high speed, I mean, they had working for many years the Emsland test facility but also the Shanghai Transrapid line in China (which is really curvy, taking account of how long the link is). Or at least they should have done it.
You can guarantee Japan's studied its effects. The Japanese consumer is pretty picky about comfort.

This is part of the reason that the mag-lev line travels in a super-straight line and has opted to tunnel through the Japanese Alps.
__________________

JuaanAcosta liked this post
bluemeansgo no está en línea   Reply With Quote
Old December 16th, 2014, 06:09 AM   #816
JuaanAcosta
Juan Acosta
 
JuaanAcosta's Avatar
 
Join Date: Sep 2014
Posts: 190
Likes (Received): 475

Quote:
Originally Posted by bluemeansgo View Post
You can guarantee Japan's studied its effects. The Japanese consumer is pretty picky about comfort.

This is part of the reason that the mag-lev line travels in a super-straight line and has opted to tunnel through the Japanese Alps.
I thought that they opted to a line mostly on tunnels because of aerodynamic-related stuff.
JuaanAcosta no está en línea   Reply With Quote
Old December 16th, 2014, 07:17 AM   #817
k.k.jetcar
Registered User
 
k.k.jetcar's Avatar
 
Join Date: Jul 2008
Location: Sapporo
Posts: 1,812
Likes (Received): 452

Likely both reasons- speeds above 320~350km/h make for extremely noisy operation, and the fastest way between two points is a straight line.
k.k.jetcar no está en línea   Reply With Quote
Old December 16th, 2014, 08:18 PM   #818
bluemeansgo
Registered User
 
bluemeansgo's Avatar
 
Join Date: Oct 2008
Posts: 451
Likes (Received): 124

Quote:
Originally Posted by JuaanAcosta View Post
I thought that they opted to a line mostly on tunnels because of aerodynamic-related stuff.
I'm not confident that it has anything to with aerodynamics, but I'd love to be proved wrong!

As I understand it, having a train inside a tunnel (unless it's a tunnel in a vacuum) creates a pressure wave that works against higher speeds. Perhaps someone who knows more about fluid dynamics can explain this better than I can, but you could liken it to a piston in a cylinder. The effect is amplified in Japanese tunnels, which are smaller diameter than European ones.

In short, tunnels can complicate operations.
bluemeansgo no está en línea   Reply With Quote
Old December 16th, 2014, 11:51 PM   #819
loefet
Registered User
 
loefet's Avatar
 
Join Date: Dec 2008
Location: G÷teborg
Posts: 525
Likes (Received): 233

The tunnels used for the Maglev are quite a bit larger than the ones used on the normal Shinkansen lines, I'm not sure but these may even be larger than the European ones.

They are there to reduce the noise of the passing trains to be able to meet the strict noise regulations that exist in Japan.
Though going through tunnels will create another problem with Tunnel booms, most above ground sections are covered to form a long tunnel, and there are just a handful of sections where the trains actually go outside then I don't think that it's as big of a problem.
And as an extra countermeasure for this effect they have added "silencers" to the entrances of the tunnels in order to mitigate the pressure waves that is cause by trains going through tunnels.

As a comparison then the more normal Shinkansen line tunnel is about 9.7 meters in diameter (number taken from the Seikan tunnel) where as the Chuo Maglev will have a tunnel diameter of 13 meters, this will make the cross section about 80% larger in the Chuo Line (when making the simplification to assume that it's a round tunnel) but the number will still be pretty close. And not only that, the cross section of the maglev trains are smaller, the L0 have a cross section that is 70% compared to the E5 train sets. So all this help to make the pressure waves in the tunnels as small as possible.
__________________

FM 2258 liked this post

Last edited by loefet; December 17th, 2014 at 12:10 AM.
loefet no está en línea   Reply With Quote
Old December 17th, 2014, 03:37 AM   #820
bluemeansgo
Registered User
 
bluemeansgo's Avatar
 
Join Date: Oct 2008
Posts: 451
Likes (Received): 124

Quote:
Originally Posted by loefet View Post
The tunnels used for the Maglev are quite a bit larger than the ones used on the normal Shinkansen lines, I'm not sure but these may even be larger than the European ones.

They are there to reduce the noise of the passing trains to be able to meet the strict noise regulations that exist in Japan.
Though going through tunnels will create another problem with Tunnel booms, most above ground sections are covered to form a long tunnel, and there are just a handful of sections where the trains actually go outside then I don't think that it's as big of a problem.
And as an extra countermeasure for this effect they have added "silencers" to the entrances of the tunnels in order to mitigate the pressure waves that is cause by trains going through tunnels.

As a comparison then the more normal Shinkansen line tunnel is about 9.7 meters in diameter (number taken from the Seikan tunnel) where as the Chuo Maglev will have a tunnel diameter of 13 meters, this will make the cross section about 80% larger in the Chuo Line (when making the simplification to assume that it's a round tunnel) but the number will still be pretty close. And not only that, the cross section of the maglev trains are smaller, the L0 have a cross section that is 70% compared to the E5 train sets. So all this help to make the pressure waves in the tunnels as small as possible.
Great information! Thanks for that. I'm a little sad that it's mostly covered. It's hard to get a sense of speed when it's all covered like that. However, I've heard that there is a possibility that in the hooded areas there's a possibility that they may have openings made in such a way that you can actually see out (due to the speed of the train). A little like you can see clearly through the metal bars on a bridge when crossing.
bluemeansgo no está en línea   Reply With Quote


Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Related topics on SkyscraperCity


All times are GMT +2. The time now is 06:26 AM.


Powered by vBulletin® Version 3.8.11 Beta 4
Copyright ©2000 - 2018, vBulletin Solutions Inc.
Feedback Buttons provided by Advanced Post Thanks / Like (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.

SkyscraperCity ☆ In Urbanity We trust ☆ about us | privacy policy | DMCA policy

tech management by Sysprosium