Templot Club Archive 2007-2020                             

topic: 1552D12 turnout geometry in EM gauge
author remove search highlighting
 
posted: 27 Jun 2011 18:51

from:

geoff
 
 

click the date to link to this post
click member name to view archived images
view images in gallery view images as slides
My question concerns a crossover that I drew ( EM gauge ) as a D12 ( facing ) and C12 ( trailing ) pair.  When you compare the switch portions of the two turnouts they are the same length although the C switch develops a greater heel opening, more angle and tighter radius.

Referring to my copy of "British Railway Track, vol1, part3" by John Morgan it looks like the C switch agrees; switch rail sits on 7+5=12 timbers.  The book seems to suggest that the D switch is 2 timbers longer; switch rail sitting on 8+6=14 timbers.

Can anyone out there please explain what's going on?

Thanks.

Geoff

posted: 27 Jun 2011 19:11

from:

Nigel Brown
 
 

click the date to link to this post
click member name to view archived images
view images in gallery view images as slides
Can't tell you what's going on, but if you select an REA type D switch and click "show switch info" then it seems to indicate there should be 14 timbers, as per the book.

In practice its probably a good idea to increase the switch length anyway to improve clearance on the model wheels, rather than go by the prototype, so I'd suggest making it somewhere in the 14-16 timbers range.

Nigel
Last edited on 27 Jun 2011 19:15 by Nigel Brown
posted: 27 Jun 2011 19:46

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
Hi Geoff,

Table 7 in BRT3 (1964) shows the same switch rail and stock rail lengths for REA C, D and E switches:

switch rail = 28ft-6in

stock rail = 36ft-0in

The virtual heel position varies of course, and different companies adopted slightly different practice in this regard. Templot follows SR practice (switches marked + in Table 7). Generally in bullhead days the SR were ahead of the pack in P.W. design.

As far as I can see Templot is correct to the REA designs marked +.

regards,

Martin.

posted: 27 Jun 2011 20:03

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
geoff wrote:
The book seems to suggest that the D switch is 2 timbers longer; switch rail sitting on 8+6=14 timbers.
p.s. Geoff,

That's correct. However 2 block chairs are beyond the switch rail joint, and 1 block chair is beyond the stock rail joint. If you put the timber numbering on in Templot you will see there are 14 S timbers.

For the C switch the last block chair is inside the switch rail joint. Templot marks the 13th timber as part of the switch (S13) so that the correct joint spacing can be included in the switch settings.

Switch rail joints are spaced 2ft-2in. Stock rail joints are spaced 2ft-0in. Table 9 in BRT3 refers.

2_271515_440000000.png2_271515_440000000.png

Martin.

posted: 27 Jun 2011 20:23

from:

geoff
 
 

click the date to link to this post
click member name to view archived images
view images in gallery view images as slides
Martin, Nigel,
Thank you for such prompt replies. Learn something every day ( forget 10 things! ). Timely reply because I was just annotating my print-outs with chair info before starting a build. Cheers.

Geoff



Templot Club > Forums > Trackbuilding topics > D12 turnout geometry in EM gauge
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