click here for a list of all existing Templot documentation
about Templot Club cookie information pre-print options:    

click image to open Templot Club in a new tab
Templot club top logo
looking for Templot? - (free)



 you are not logged in  - Login | Join


receive all messages by email: info


Recent Topics
Front Page  Search  Image Gallery  Gallery Upload  My Account  Members  Help  
make a donation  
please click: important information for new members and first-time visitors Templot Companion - User Guide
            messages archive on Yahoo
page trail:  Templot Club > Forums > Baffled beginners > sleeper interlacing - Midland Railway stretcher bars
Templot web site

                                       sleeper interlacing - Midland Railway stretcher bars
  Page:  First Page Previous Page  1  2       
 Start new topic   Reply blank   Printer friendly 
  Rate this topic  
AuthorMessage
 Clicked a link? Wrong message? Wait until the page has finished loading, click in the address bar and then press the Enter key. This is a timing bug in some browsers.
41st message | this message only posted: 21 Oct 2017 09:46
 PM  Reply with quote  Reply blank 
from:
Tim Lee
London, United Kingdom

 

view images in gallery
view images as slides
Here is another example which also appears to have the rodding unconnected with the stretcher bars
__________
message ref: 22491

 
 Clicked a link? Wrong message? Wait until the page has finished loading, click in the address bar and then press the Enter key. This is a timing bug in some browsers.
42nd message | this message only posted: 21 Oct 2017 10:17
 PM  Reply with quote  Reply blank 
from:
Ariels Girdle
 

 

view images in gallery
view images as slides
I tend to agree. You seem to be opening up a real can of worms here.
__________
message ref: 22492

 
 Clicked a link? Wrong message? Wait until the page has finished loading, click in the address bar and then press the Enter key. This is a timing bug in some browsers.
43rd message | this message only posted: 21 Oct 2017 11:26
 PM  Reply with quote  Reply blank 
from:
John Palmer
 

 

view images in gallery
view images as slides
The purpose of detection is to prove that a point tongue has assumed the correct position for clearance of its related signal. For this reason a detector rod is connected to a point tongue (toe of switch), rather than to the stretcher bar. If the detector rod were attached to the stretcher bar and that stretcher had become disconnected from its associated switch rails, detection would prove nothing about the position of the switch tongues.

In the Getty image, the detector rod is attached to the open switch tongue furthest from the detector This is consistent with the adjacent ground signal reading only over one route, probably that diverging to the left. Assuming the picture shows both signal and points in the 'normal' position, the detection arrangement proves that the tongue shown open in the picture has nestled in the closed position against its adjacent stock rail when the points are reversed, and that the associated signal can be cleared. It may be of interest that the IRSE booklet dealing with detection (1969 edition) suggests that in a comparable situation the normal arrangement would be to connect the detector blade to the normally closed switch tongue.

If the signal for which detection is provided reads over both routes through the points detected, then blades for both switch tongues will be provided in the detector and connected to their respective tongues by independent rods.

It seems to me that there is a flaw in the logic of detecting one tongue only. In such a case, if the undetected tongue has become disconnected from its stretcher you may end up with both tongues in the open position or both in the closed position (depending on which tongue has become disconnected). Detection then provides false 'proof' that the points have assumed the correct position, but a derailment on the switch has become almost inevitable.

__________
message ref: 22493

 
 Clicked a link? Wrong message? Wait until the page has finished loading, click in the address bar and then press the Enter key. This is a timing bug in some browsers.
44th message | this message only posted: 21 Oct 2017 11:33
 PM  Reply with quote  Reply blank 
from:
Tim Lee
London, United Kingdom

 

view images in gallery
view images as slides
Thanks John,

Glad I was reading the arrangement correctly ... appreciate the explanation - I now have a better handle on why!
__________
message ref: 22494

 
 Clicked a link? Wrong message? Wait until the page has finished loading, click in the address bar and then press the Enter key. This is a timing bug in some browsers.
45th message | this message only posted: 21 Oct 2017 11:45
 PM  Reply with quote  Reply blank 
from:
Martin Wynne
West Of The Severn, United Kingdom



view images in gallery
view images as slides

Please do not send requests for help direct to me via email or PM.

Post your questions on the forum where everyone can see them and add helpful replies.
John Palmer wrote: It seems to me that there is a flaw in the logic of detecting one tongue only. In such a case, if the undetected tongue has become disconnected from its stretcher you may end up with both tongues in the open position or both in the closed position (depending on which tongue has become disconnected). Detection then provides false 'proof' that the points have assumed the correct position, but a derailment on the switch has become almost inevitable.Hi John,

In the early days there was little thought about disconnected or broken stretcher rods. On the face of it, that should be a very unlikely occurrence given the amount of staff then available for track maintenance. Nowadays we know different after recent major incidents:

 https://assets.digital.cabinet-office.gov.uk/media/547c9037ed915d4c0d000199/R202008_081023_Grayrigg_v5.pdf

The important thing then was to detect that the relevant switch blade was properly closed against the stock rail, before the signal can clear. That's something beyond mechanical failure, and much more likely to go wrong, such as weather conditions or fallen debris affecting the rodding run or clogging the switch blade.

regards,

Martin.


__________
message ref: 22495

 
 Clicked a link? Wrong message? Wait until the page has finished loading, click in the address bar and then press the Enter key. This is a timing bug in some browsers.
46th message | this message only posted: 21 Oct 2017 12:07
 PM  Reply with quote  Reply blank 
from:
Tim Lee
London, United Kingdom

 

view images in gallery
view images as slides
Here is another image which again shows the 180 degree actuation rod bend locating into the switch independent of the front stretcher bar. Masborough, 1907 It does seem to suggest that pre WWI at least the Midland connected rodding independently of the front stretcher bar certainly within sidings and goods yards. I am still hoping to turn up a mainline trailing turnout to see if the practice differed  - we know it was different for facing due to the requirement for locking.



__________
message ref: 22496

 
 Clicked a link? Wrong message? Wait until the page has finished loading, click in the address bar and then press the Enter key. This is a timing bug in some browsers.
47th message | this message only posted: 21 Oct 2017 14:20
 PM  Reply with quote  Reply blank 
from:
John Palmer
 

 

view images in gallery
view images as slides
Martin Wynne wrote: In the early days there was little thought about disconnected or broken stretcher rods. On the face of it, that should be a very unlikely occurrence given the amount of staff then available for track maintenance. Nowadays we know different after recent major incidents:

 https://assets.digital.cabinet-office.gov.uk/media/547c9037ed915d4c0d000199/R202008_081023_Grayrigg_v5.pd
Indeed, Martin, and it was not merely the number of available staff that mitigated the risk, but the frequency of inspection. I understand that a daily inspection of running lines had become accepted practice by the mid 1860's, but that state of affairs has to be contrasted with the regime in place by the time of Grayrigg, as the report you linked indicates that “For Category 1 track, inspections were required weekly with a maximum interval between inspections of eight days.” This represented a major change that could be justified by the greater reliability of modern track, but which nonetheless enlarged the risk of defects that might have become apparent from a daily inspection remaining undetected for extended periods – as at Grayrigg.


I may have misinterpreted the IRSE's suggestion as to which tongue should be detected in a single detection arrangement. Looking at 'Railway Signalling and Communications', it seems that the tongue to be detected in such a case is the one that needs to be closed in order for the related signal to be cleared. Generally this will be the tongue that is open when the switch lies normal. I don't think this affects my conclusion that the logic is flawed, inasmuch as any failure of both tongues to move creates the conditions for a derailment, regardless of whether such failure results from disconnection of tongue from stretcher, weather-related reasons or debris fouling the connections.

__________
message ref: 22497

 
 Clicked a link? Wrong message? Wait until the page has finished loading, click in the address bar and then press the Enter key. This is a timing bug in some browsers.
48th message | this message only posted: 22 Oct 2017 08:06
 PM  Reply with quote  Reply blank 
from:
Tim Lee
London, United Kingdom

 

view images in gallery
view images as slides
Next Question ......
If we assume that for sidings etc at least, pre WWI turnouts were activated by an independent fixing of the point rodding to the nearest switch blade, can we assume that the rod itself would prevent the point blade rising or moving in relation to the stock rail (apart from laterally). 
If this is the case, and looking at the drawing which Martin posted earlier -

would it be right to assume that the extension shown on the right hand side of the drawing projecting through the stock rail, achieves the same thing on the side opposite to the actuation rod?

Edit - correction, looking again at the drawing it would appear that there is no extension through the stock rail - I assume therefore that the switchblade relies on the undercut of the planing to ensure against lift? Am I right in assuming that the extension is primarily used where the stock rail is joggled?

__________
message ref: 22506

 
 Clicked a link? Wrong message? Wait until the page has finished loading, click in the address bar and then press the Enter key. This is a timing bug in some browsers.
49th message | this message only posted: 23 Oct 2017 14:16
 PM  Reply with quote  Reply blank 
from:
Tim Lee
London, United Kingdom

 

view images in gallery
view images as slides
A couple of further images which might suggest this practice on rodding was not limited to sidings etc.


__________
message ref: 22525

 
 Clicked a link? Wrong message? Wait until the page has finished loading, click in the address bar and then press the Enter key. This is a timing bug in some browsers.
50th message | this message only posted: 23 Oct 2017 14:45
 PM  Reply with quote  Reply blank 
from:
Martin Wynne
West Of The Severn, United Kingdom



view images in gallery
view images as slides

Please do not send requests for help direct to me via email or PM.

Post your questions on the forum where everyone can see them and add helpful replies.
Hi Tim,
 
Interesting that in the first pic there are 2 timbers in the switch front. In the second pic only 1 timber. Something else to get right, when adding the fishplates.
 
Nowadays the switch front timbers are indeed timbers (12" wide). In pre-group days they were often plain sleepers (10" wide). Templot does include an option for this in the custom switch settings.
 
So that's two more things to get exactly right in the face of conflicting evidence.
 
Anyone got a pic showing a switch front of 2 timbers, one a timber and the other a sleeper?
 
regards,
 
Martin.

__________
message ref: 22526

 
 Clicked a link? Wrong message? Wait until the page has finished loading, click in the address bar and then press the Enter key. This is a timing bug in some browsers.
51st message | this message only posted: 23 Oct 2017 19:14
 PM  Reply with quote  Reply blank 
from:
Tim Lee
London, United Kingdom

 

view images in gallery
view images as slides
Thought it might be useful to load this MR drawing of switch blades and stretcher bars for information.
__________
message ref: 22529
Attachment: DSC_0012.JPG (Downloaded 19 times)
 
 Clicked a link? Wrong message? Wait until the page has finished loading, click in the address bar and then press the Enter key. This is a timing bug in some browsers.
52nd message | this message only posted: 30 Oct 2017 09:07
 PM  Reply with quote  Reply blank 
from:
Tim Lee
London, United Kingdom

 

view images in gallery
view images as slides
Does anybody have any drawings or images which might describe the connection for circular bar rodding to an intemediary crank within the rod length when two sets of points have to work together ... ie for a crossover on running lines. I am trying to work out how the connection from the bar would have been worked (easy to find examples of channel rodding but not circular).
It is the equivalent of this connection but to a bar I am looking for


Used to move the crank 'B' on the attached diagram



Thanks

Tim

__________
message ref: 22655

 
 Clicked a link? Wrong message? Wait until the page has finished loading, click in the address bar and then press the Enter key. This is a timing bug in some browsers.
53rd message | this message only posted: 30 Oct 2017 14:08
 PM  Reply with quote  Reply blank 
from:
Tim Lee
London, United Kingdom

 

view images in gallery
view images as slides


I have been kindly sent these ... so all good
Tim





__________
message ref: 22656

 
 Clicked a link? Wrong message? Wait until the page has finished loading, click in the address bar and then press the Enter key. This is a timing bug in some browsers.
54th message | this message only posted: 2 Nov 2017 00:44
 PM  Reply with quote  Reply blank 
from:
Tony W
North Notts., United Kingdom

 

view images in gallery
view images as slides
Tim Lee wrote: Next Question ......
If we assume that for sidings etc at least, pre WWI turnouts were activated by an independent fixing of the point rodding to the nearest switch blade, can we assume that the rod itself would prevent the point blade rising or moving in relation to the stock rail (apart from laterally). 
If this is the case, and looking at the drawing which Martin posted earlier -

would it be right to assume that the extension shown on the right hand side of the drawing projecting through the stock rail, achieves the same thing on the side opposite to the actuation rod?

Edit - correction, looking again at the drawing it would appear that there is no extension through the stock rail - I assume therefore that the switchblade relies on the undercut of the planing to ensure against lift? Am I right in assuming that the extension is primarily used where the stock rail is joggled?
Hi Tim.
I think these stretcher rods are specials for Three throw blades only. See my pictures in message 13 where it is quite clear that the parallel extension is used to allow the stretcher rod to connect to the short inner blade (via the key hole slot) whilst passing through the hole in the longer outer blade without restricting its free movement.
Regards
Tony.

__________
message ref: 22673

 
 Clicked a link? Wrong message? Wait until the page has finished loading, click in the address bar and then press the Enter key. This is a timing bug in some browsers.
55th message | this message only posted: 2 Nov 2017 08:30
 PM  Reply with quote  Reply blank 
from:
Tim Lee
London, United Kingdom

 

view images in gallery
view images as slides
Tony W wrote:Hi Tim.
I think these stretcher rods are specials for Three throw blades only. See my pictures in message 13 where it is quite clear that the parallel extension is used to allow the stretcher rod to connect to the short inner blade (via the key hole slot) whilst passing through the hole in the longer outer blade without restricting its free movement.
Regards
Tony.
Of course .... now you say it that makes total sense.
Thanks

Tim

__________
message ref: 22677

 
This is topic ID = 2839     Page created at 02:50 (local time) Page:  First Page Previous Page  1  2     
You can type a quick reply to this topic here.

Click in the box to begin.


But to reply to an individual message, or to include images, attachments and formatted text, use the reply buttons on each message above.

To start a new topic in this forum, click the Start new topic button below.
To start a new topic in a different forum, click the Forum Jump drop-down list below.

             Start new topic 

 click to jump to a different forum:     Back to top of page

Templot Club > Forums > Baffled beginners > sleeper interlacing - Midland Railway stretcher bars
about Templot Club

list recently active topics Templot Companion - User Guide - A-Z Index Old Templot Companion Please click: important information for new members and first-time visitors.
indexing link for search engines only

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.  
© 2017  

Powered by UltraBB - © 2009 Data 1 Systems