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 March 7th, 2012, 04:55 AM   #1
Nexis
Dark Wolf
 
Nexis's Avatar
 
Join Date: Aug 2007
Location: Along the Rails of North Jersey..
Posts: 15,684
Likes (Received): 17032

MISC | Which type of Tie/Sleeper is best for a Railroad?

Recently there have been issues with the Concrete ties in this region , with them cracking and not allowing the water to drain effectively. Is it the fact that the ballast isn't laid properly or the fact that the ties aren't high quality meaning theres flawed contracting. Wooden and Rubber ties haven't had this issue , and some people think its Concrete. I honestly doubt its the concrete , except with the cracking and that in my opinion is due to the bad contracting and quality... Where should concrete ties be used and where shouldn't they be used?
__________________
My FLICKR Page < 54,100+ Photos of Urban Renewal , Infrastructure , Food and Nature in the Northeastern US
Visit the Reorganized New York City Section
My Photography Website
Visit the New Jersey Section
Nexis no está en línea   Reply With Quote

Sponsored Links
Old March 7th, 2012, 07:47 AM   #2
Silver Swordsman
Registered User
 
Join Date: Nov 2011
Posts: 371
Likes (Received): 101

The reason why "wooden tracks" don't have this kind of problem is because 1) they are replaced much more often than concrete ties are and 2) trains travelling on track using wooden ties go at reduced speeds, which reduce wear on the infrastructure. The only issue that I've read about concrete cracking is from the KTX in Korea, where the construction company given the contract for the trackbed actually had no experience in the field: the rubber pieces holding the track screws in place absorbed rainwater, and when winter set in, froze and expanded, thus cracking the concrete. Speaking of heat expansion, the fact that wood expands much more readily than concrete may be an explanation as to why it doesn't crack as much.

Water's got nothing to do with cracking concrete: in fact, many high speed systems now use ballastless track in which the track is directly fastened to a concrete bed. I doubt that cold is the direct result of the concrete cracks in your area: the Japanese shinkansen has been using concrete slab track for fifty years without a hitch. Therefore, I agree with you that it was probably poor construction quality instead of the inherent nature of concrete itself: personally, I feel that all ties should be converted to concrete as soon as possible--especially in the US.
__________________
My Virtual-Model Railroad: High Speed Rail in RCT3
Project Anniversary: Click Here
Silver Swordsman no está en línea   Reply With Quote
Old March 7th, 2012, 08:42 AM   #3
Suburbanist
on the road
 
Suburbanist's Avatar
 
Join Date: Dec 2009
Location: the rain capital of Europe
Posts: 27,525
Likes (Received): 21227

Balastless tracks are the way to go IMHO. They spread vibration better and although expensive require far less maintenance over time.
__________________
YIMBY - Yes, in my backyard!
Suburbanist no está en línea   Reply With Quote
Old March 7th, 2012, 09:27 AM   #4
K_
Registered User
 
Join Date: Jan 2010
Posts: 2,744
Likes (Received): 243

Quote:
Originally Posted by Silver Swordsman View Post
The only issue that I've read about concrete cracking is from the KTX in Korea, where the construction company given the contract for the trackbed actually had no experience in the field: the rubber pieces holding the track screws in place absorbed rainwater, and when winter set in, froze and expanded, thus cracking the concrete. Speaking of heat expansion, the fact that wood expands much more readily than concrete may be an explanation as to why it doesn't crack as much.
Deutsche Bahn also had problems with concrete Ties on Berlin - Hamburg, but there the cause was a subcontractor using substandard concrete.

Nowadays many railroads go all concrete. Conventional lines use concrete ties, and even the ties underneath switches are concrete. For high speed and tunnel tracks continuous concreted roadbeds are becoming the norm.
K_ no está en línea   Reply With Quote
Old March 7th, 2012, 10:38 AM   #5
Silver Swordsman
Registered User
 
Join Date: Nov 2011
Posts: 371
Likes (Received): 101

Quote:
Originally Posted by Suburbanist View Post
Balastless tracks are the way to go IMHO. They spread vibration better and although expensive require far less maintenance over time.
I disagree with your claim that ballastless track is better vibration-wise. The thing is, wood absorbs vibrations, making it less loud. When we're using ballastless slab track, not only are the sounds directly reflected and amplified by the concrete, but the very vibrations from the train penetrate deeper into the ground and are felt much more strongly than ordinary tracks. I've stood next to high speed trains travelling at full speed before: the very ground and air trembles.
__________________
My Virtual-Model Railroad: High Speed Rail in RCT3
Project Anniversary: Click Here
Silver Swordsman no está en línea   Reply With Quote
Old March 7th, 2012, 01:50 PM   #6
Suburbanist
on the road
 
Suburbanist's Avatar
 
Join Date: Dec 2009
Location: the rain capital of Europe
Posts: 27,525
Likes (Received): 21227

Low-frequency vibrations do, indeed, spread more in concrete than through irregular materials (think of you being in a concrete high-rise and listening some weird vibrations from someone blasting loud speakers beneath you).

However, one should compare trains travelling at similar speeds with similar tracks. Wooden ties would have to be replaced every year or less if they were used for high-speed tracks and it would be more dangerous for the trains in some "tighter" high-speed curves.

That is why they build extensive noise barriers around ballastless tracks, which doubles as safety barriers.

Finally, under high speed traffic, the usual size of ballast rocks is prone to be jettisoned in the air by passing trains. That can harm trains, traffic passing under an overpass, and requires more frequent maintenance.
__________________
YIMBY - Yes, in my backyard!
Suburbanist no está en línea   Reply With Quote
Old March 7th, 2012, 02:02 PM   #7
K_
Registered User
 
Join Date: Jan 2010
Posts: 2,744
Likes (Received): 243

Quote:
Originally Posted by Silver Swordsman View Post
I disagree with your claim that ballastless track is better vibration-wise. The thing is, wood absorbs vibrations, making it less loud. When we're using ballastless slab track, not only are the sounds directly reflected and amplified by the concrete, but the very vibrations from the train penetrate deeper into the ground and are felt much more strongly than ordinary tracks. I've stood next to high speed trains travelling at full speed before: the very ground and air trembles.
On German HSLs they now put sound absorbing material on top ob the slab, between and alongside the tracks. Makes a big difference too.
K_ no está en línea   Reply With Quote
Old March 7th, 2012, 02:04 PM   #8
K_
Registered User
 
Join Date: Jan 2010
Posts: 2,744
Likes (Received): 243

Quote:
Originally Posted by Suburbanist View Post
Finally, under high speed traffic, the usual size of ballast rocks is prone to be jettisoned in the air by passing trains. That can harm trains, traffic passing under an overpass, and requires more frequent maintenance.
Ballast however has the big advantage that it is easy to correct the track geometry afterwards to compensate for terrain movements...
K_ no está en línea   Reply With Quote
Old March 7th, 2012, 02:08 PM   #9
Suburbanist
on the road
 
Suburbanist's Avatar
 
Join Date: Dec 2009
Location: the rain capital of Europe
Posts: 27,525
Likes (Received): 21227

Quote:
Originally Posted by K_ View Post
Ballast however has the big advantage that it is easy to correct the track geometry afterwards to compensate for terrain movements...
Indeed. Correcting geometry for ballasless tracks is expensive. But it can be done. They are good for high-trafficked high-speed lines because they greatly increase their reliability without travel speed compromises.
__________________
YIMBY - Yes, in my backyard!
Suburbanist 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 12:02 PM.


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