Templot Club Archive 2007-2020                             

topic: 966Superelevation
author remove search highlighting
 
posted: 29 Oct 2009 16:00

from:

Alan McMillan
 
Edinburgh - United Kingdom

click the date to link to this post
click member name to view archived images
view images in gallery view images as slides
Hello all.

Does anybody know what to do with a crossover (as shown below) on a curve? I can't really see what would be the solution as the normal arrangement for superelevated curves is as illustrated which would lead to the crossover track doing some very strange things to go from one line to the other.

Regards

Alan McMillan

 

 

412_291058_530000000.png412_291058_530000000.png


412_291058_330000000.png412_291058_330000000.png


posted: 29 Oct 2009 16:31

from:

allanferguson
 
Fife - United Kingdom

click the date to link to this post
click member name to view archived images
view images in gallery view images as slides
Alan

The  interim  report  on  the  Grayrigg  smash 

http://www.raib.gov.uk/cms_resources.cfm?file=/071003_IR022007_Grayrigg.pdf

has  a  picture  of  the  offending  crossover  which  suggests  that  both  tracks  were  in  the  same  plane  at  a  cant  of  95mm,  at  least  in  the  vicinity  of  the  crossover.  I  feel  sure  I've  heard  of  situations  where  the  cant  was  taken  out  through  a  crossover,  but  this  would  involve  a  speed  reduction,  and  in  any  case  I  can't  think  of  examples,  so  may  be  havering!

Allan  Ferguson

posted: 29 Oct 2009 17:06

from:

Alan McMillan
 
Edinburgh - United Kingdom

click the date to link to this post
click member name to view archived images
view images in gallery view images as slides
Thanks Allan

I did wonder if this was how it was done - the only thing was I'd never actually seen it and I wanted to make sure that my approach was prototypical. At least it will make the thing easier to build!

Regards

Alan

posted: 29 Oct 2009 17:31

from:

John Lewis
 
Croydon - United Kingdom

click the date to link to this post
click member name to view archived images
view images in gallery view images as slides
From
Alan McMillanEm dinburgh, United Kingdom


Hello all.

> Does anybody know what to do with a crossover (as shown below) on a curve? I can't really see what would be the solution as the normal arrangement for superelevated curves is as illustrated which would lead to the crossover track doing some very strange things to go from one line to the other.



Apparently the ideal was to keep the rails all in the same plane using very long sleepers under all tracks.

However "British Railways Track" has pictures (1st Edn Pg 68) of some "two level" chairs introduced by the LMS where the base of the chair under the rail was thicker than normal to preserve the vertical alignment. The use of these meant the six foot way had to be increased in width. Perhaps Martin or someone can explain furtheer, please?

The worse case is double junctions where the branch is on the outside of the curve, but itself curves in the same direction as the main. Care has to be taken to avoid the branch rail on the inside of the curve becoming higher than the outer rail of the branch.

posted: 29 Oct 2009 18:03

from:

Alan McMillan
 
Edinburgh - United Kingdom

click the date to link to this post
click member name to view archived images
view images in gallery view images as slides
Hi John

Your last point is interesting. There used to be a very strange arrangement at Carstairs Junction on the Scottish Region in the 1970s where the Edinburgh branch track deviated from the up main platform road which had a 6 inch cant deficiency for high speed through running. I used to see Brush Type 4s that had brought in the Edinburgh portion of London bound trains use this to reach their stabling sidings. (In those days they swapped motive power prior to electrification of the Edinburgh line). The branch deviated fairly sharply to the left from the main which was heading right. The locomotives effectively climbed over the top of the outer main line rail on a right hand cant and then coggled over alarmingly to the left hand cant of the branch. I've never seen this anywhere else and I'm sure if you modelled it you'd be told by all and sundry that a formation like that would never exist in the real world! Maybe someone has a photo of this?

Regards

Alan

posted: 29 Oct 2009 18:31

from:

Martin Wynne
 
West Of The Severn - United Kingdom

click the date to link to this post
click member name to view archived images
view images in gallery view images as slides
Alan McMillan wrote:
Does anybody know what to do with a crossover (as shown below) on a curve? I can't really see what would be the solution as the normal arrangement for superelevated curves is as illustrated which would lead to the crossover track doing some very strange things to go from one line to the other.

412_291058_330000000.png412_291058_330000000.png
Hi Alan,

Previous discussion about this is at:

topic 150

There is more discussion and a long extract from BRT about 2-level chairs at:

http://groups.yahoo.com/group/templot/message/4693

regards,

Martin.

posted: 29 Oct 2009 18:43

from:

Alan McMillan
 
Edinburgh - United Kingdom

click the date to link to this post
click member name to view archived images
view images in gallery view images as slides
Thanks Martin, but I think I'll stick to the "all rails in the same plane" approach. Two level chairs sound like a nightmare and since I'm doing this in flat bottom and using timber and rivet construction, I think I'll raise the white flag and go for the easy option.

Regards

 

Alan McMillan

posted: 29 Oct 2009 20:54

from:

Jamie92208
 
 

click the date to link to this post
click member name to view archived images
view images in gallery view images as slides
I think that the same plane idea is the right one.  I read an accident report recently that dealt with a freight train derailing on one of the Tyne bridges.  From memory one of the causes was superelevation on the main line but not on the diverging route, this combined with a badly maintained suspension on an MGR wagon to cause a derailment.  Keeping everything in the same plane solves a multitude of potential sins.  Our models aren't as good as the real thin at stayin on the track.

 

Jamie

posted: 29 Oct 2009 21:00

from:

Alan McMillan
 
Edinburgh - United Kingdom

click the date to link to this post
click member name to view archived images
view images in gallery view images as slides
I just remember how that Brush 4 looked at Carstairs - it was a derailment waiting to happen - and in P87 it probably would!

 

Alan

posted: 30 Oct 2009 09:15

from:

Jamie92208
 
 

click the date to link to this post
click member name to view archived images
view images in gallery view images as slides
Remembering more about that accident report. In 12 inches to the foot minor changes in the set up of the wagon's suspension coupled with poor maintenance of the track brought a wheelset, with several tons holding each axle down, off the track.  I don't hold out much hope for our hobby when you are talking about a few gramms of adhesion weight in some cases.  Stick to the same plane.

posted: 2 Nov 2009 23:35

from:

allanferguson
 
Fife - United Kingdom

click the date to link to this post
click member name to view archived images
view images in gallery view images as slides
For  a  good  illustration  of  the  cant  problem  see  this  site

http://www.jhowie.force9.co.uk/carstairs.htm#negative%20cant

You  can  get  quite  seasick  watching  one  of  the  NXEC  sets  coming  through!

Allan  Ferguson

posted: 3 Nov 2009 10:49

from:

Alan McMillan
 
Edinburgh - United Kingdom

click the date to link to this post
click member name to view archived images
view images in gallery view images as slides
It's actually worse than I remember it! Modelling something like that would be nightmarish!

Alan McMIllan



Templot Club > Forums > Templot talk > Superelevation
about Templot Club

Templot Companion - User Guide - A-Z Index Templot Explained for beginners Please click: important information for new members and first-time visitors.
indexing link for search engines

back to top of page


Please read this important note about copyright: Unless stated otherwise, all the files submitted to this web site are copyright and the property of the respective contributor. You are welcome to use them for your own personal non-commercial purposes, and in your messages on this web site. If you want to publish any of this material elsewhere or use it commercially, you must first obtain the owner's permission to do so.
The small print: All material submitted to this web site is the responsibility of the respective contributor. By submitting material to this web site you acknowledge that you accept full responsibility for the material submitted. The owner of this web site is not responsible for any content displayed here other than his own contributions. The owner of this web site may edit, modify or remove any content at any time without giving notice or reason. Problems with this web site? Contact webmaster@templot.com.   This web site uses cookies: click for information.  
© 2020  

Powered by UltraBB - © 2009 Data 1 Systems