Templot Club Archive 2007-2020                             

topic: 3095Moretonhampstead from OS Maps - BR (W) 1948 - 1958
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posted: 6 Oct 2017 12:30

from:

David Higgs
 
Bletchley - United Kingdom

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Having had a lifelong interest in British Railways it has been an ambition of mine to build a BR (W) Branch line Terminus in 4 mm (EM Gauge).  Having looked at the prototypes of Ashburton, Marlow, Moretonhampstead, Wallingford and Watlington for inspiration I decided on Moretonhampstead.
 
About 5 years ago I set about constructing an Outbuilding to house the Layout and the ever-increasing Railway related items I have collected over the years. Two years ago, I was made redundant and decided that I would take early retirement and so I find I have a little more time to re-kindle my Model Railway Interests.
 
I first acquired Templot over 14 years ago and have only really dabbled with it on sporadic occasions. I have attached a copy of my Templot Box File and Background Shapes of where I got to around 4 years ago. I am basically at the stage of having to re-learn Templot almost from the beginning although I have followed the progress on the Templot Forum.
 
The recent discussion on importing and using Maps as Background Shapes has also spurred me along. I did import a Map of Moretonhampstead that I copied from one of the many books that I have acquired. It compares reasonably well with the 25” Maps of the NLS. I’m not too sure if I have used the correct style of Turnout. The 1 in 8.25 RAM / CLM seems an odd size E.g:-
 
REA semi-curved  C-size left-hand switch (unjoggled) 1 in 8.25 RAM ( 1 in 8.28 CLM ) regular V-crossing
equalized-incremental timbering.
 
Anyway that’s where I am at.

Regards

David
Attachment: attach_2515_3095_moretonhampstead_2017_10_06_1108_32.box     307
Last edited on 14 Oct 2017 10:36 by David Higgs
posted: 6 Oct 2017 12:31

from:

David Higgs
 
Bletchley - United Kingdom

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This the original Background Shape I was using.
Attachment: attach_2516_3095_start.bgs     289

posted: 6 Oct 2017 15:58

from:

Martin Wynne
 
West Of The Severn - United Kingdom

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David Higgs wrote:
This the original Background Shape I was using.
Hi David,

Thanks for that, but you need to upload also the start.sk81 image file.

All anyone can see at present is a blank rectangle.

regards,

Martin.

posted: 6 Oct 2017 16:33

from:

Martin Wynne
 
West Of The Severn - United Kingdom

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David Higgs wrote:
It compares reasonably well with the 25” Maps of the NLS. I’m not too sure if I have used the correct style of Turnout. The 1 in 8.25 RAM / CLM seems an odd size E.g:-
 
REA semi-curved  C-size left-hand switch (unjoggled) 1 in 8.25 RAM ( 1 in 8.28 CLM ) regular V-crossing equalized-incremental timbering.
Hi David,

It's very unlikely to be that size. Especially the REA switch on a GWR branch line, although you never say never.

In order to determine exact turnout sizes from an OS map, several settings need to be made:

1. You must use an exact scale track gauge, such as P4, S7, etc.

EM turnouts are shorter than the same size in P4.

2. You need to use CLM crossing angles. Templot uses RAM angles by default.

3. For many/most sizes of turnout, you need to change to generic V-crossings.

4. On the GWR the 6ft way is 1/2" wider* than other companies, so for extreme accuracy you need to set 134.5" instead of 134" double-track spacing. It makes a small difference to the length of crossovers.

*this is a legacy from the earlier use of 3" wide rail.

Looking at the 1936 map of Moretonhampstead, it is clear that the platform release crossover has been changed from the earlier maps. It is longer, and moved under the train shed, presumably to make a longer loco release.

The question is, when did that renewal take place? The GWR introduced their range of flexible switches (including C) in the early 1930s. So it's feasible that by 1936 one of those had been installed brand new at the terminus of the Moretonhampstead branch.

Feasible, but not I think very likely, unless you have direct evidence? The renewal may have taken place earlier, and even if not, it's far more likely that a second-hand old-type switch would have been used, possibly resulting from the use of a new C switch on the main lines somewhere else.

Fortunately the 1936 map shows the switch toe marks at both end of the crossover, so by trial and error we can arrive at a turnout size which fits (assuming both turnouts are the same size -- it would be very unusual if not in a straight crossover).

And the result seems to be a GWR 18ft straight switch and 1:10 CLM crossing (which is a bog-standard GWR size):

2_061122_290000000.png2_061122_290000000.png

That's in P4. For EM it will be a bit shorter, but you could use 1:10 RAM instead of CLM (which will lengthen it a fraction), and centralize it between the crossover toe marks on the map.

regards,

Martin.

posted: 6 Oct 2017 16:51

from:

David Higgs
 
Bletchley - United Kingdom

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Martin Wynne wrote:
David Higgs wrote:
This the original Background Shape I was using.
Hi David,

Thanks for that, but you need to upload also the start.sk81 image file.

All anyone can see at present is a blank rectangle.

regards,

Martin.
I don't seem to be having any luck in uploading the start.sk81 image file.

posted: 6 Oct 2017 17:00

from:

Martin Wynne
 
West Of The Severn - United Kingdom

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David Higgs wrote:
I don't seem to be having any luck in uploading the start.sk81 image file.
Hi David,

How big is it? Attachments are limited to 10MB max.

If no joy, send it to me in an email, and I will upload it for you.

You can find my email address by clicking on my name on the left > View Profile.

regards,

Martin.

posted: 7 Oct 2017 11:25

from:

Nigel Brown
 
 

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Martin Wynne wrote:
David Higgs wrote:
It compares reasonably well with the 25” Maps of the NLS. I’m not too sure if I have used the correct style of Turnout. The 1 in 8.25 RAM / CLM seems an odd size E.g:-
 
REA semi-curved  C-size left-hand switch (unjoggled) 1 in 8.25 RAM ( 1 in 8.28 CLM ) regular V-crossing equalized-incremental timbering.
Hi David,

It's very unlikely to be that size. Especially the REA switch on a GWR branch line, although you never say never.

In order to determine exact turnout sizes from an OS map, several settings need to be made:

1. You must use an exact scale track gauge, such as P4, S7, etc.

EM turnouts are shorter than the same size in P4.

2. You need to use CLM crossing angles. Templot uses RAM angles by default.

3. For many/most sizes of turnout, you need to change to generic V-crossings.

4. On the GWR the 6ft way is 1/2" wider* than other companies, so for extreme accuracy you need to set 134.5" instead of 134" double-track spacing. It makes a small difference to the length of crossovers.

*this is a legacy from the earlier use of 3" wide rail.

Looking at the 1936 map of Moretonhampstead, it is clear that the platform release crossover has been changed from the earlier maps. It is longer, and moved under the train shed, presumably to make a longer loco release.

The question is, when did that renewal take place? The GWR introduced their range of flexible switches (including C) in the early 1930s. So it's feasible that by 1936 one of those had been installed brand new at the terminus of the Moretonhampstead branch.

Feasible, but not I think very likely, unless you have direct evidence? The renewal may have taken place earlier, and even if not, it's far more likely that a second-hand old-type switch would have been used, possibly resulting from the use of a new C switch on the main lines somewhere else.

Fortunately the 1936 map shows the switch toe marks at both end of the crossover, so by trial and error we can arrive at a turnout size which fits (assuming both turnouts are the same size -- it would be very unusual if not in a straight crossover).

And the result seems to be a GWR 18ft straight switch and 1:10 CLM crossing (which is a bog-standard GWR size):

2_061122_290000000.png2_061122_290000000.png

That's in P4. For EM it will be a bit shorter, but you could use 1:10 RAM instead of CLM (which will lengthen it a fraction), and centralize it between the crossover toe marks on the map.

regards,

Martin.
 
Martin

I may be wrong but I thought the GWR 6-foot way was 6' 6", not 6' 0.5" ?

Cheers
Nigel

posted: 7 Oct 2017 12:12

from:

Martin Wynne
 
West Of The Severn - United Kingdom

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Nigel Brown wrote:
I may be wrong but I thought the GWR 6-foot way was 6' 6", not 6' 0.5" 
Hi Nigel,

6ft-6in to the gauge-faces. With 2 rails 2.75in wide that leaves 6ft-0.1/2in between them.

i.e. 1/2in wider than the usual 6ft way on other lines.

regards,

Martin.

posted: 7 Oct 2017 13:06

from:

Nigel Brown
 
 

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Martin Wynne wrote:
Nigel Brown wrote:
I may be wrong but I thought the GWR 6-foot way was 6' 6", not 6' 0.5" 
Hi Nigel,

6ft-6in to the gauge-faces. With 2 rails 2.75in wide that leaves 6ft-0.1/2in between them.

i.e. 1/2in wider than the usual 6ft way on other lines.

regards,

Martin.
Hi Martin

Ah, so the other lot measured it in a different way. Didn't realise that. Did notice when I checked that Smith has it measured to the gauge faces.

It does mean that my layout, where I used 6' between the rails then later thought I had it wrong, is in fact correct, more or less :)

Cheers
Nigel


posted: 8 Oct 2017 11:04

from:

David Higgs
 
Bletchley - United Kingdom

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Hello Martin,


Thank you for your very informative reply, much appreciated.


I wasn’t too sure on what specification for the Turnout Switch / Crossings I should be using so thanks for that.


I’ve uploaded 3 images of Moretonhampstead to show the Engine Release Crossover and the Goods Yard Crossover. 


Now that I have more time available, more information to hand, plus the availability of the 25” Maps from NLS I think this will be an ideal opportunity to start my Moretonhampstead project afresh. I will post my progress to this thread.






Last edited on 8 Oct 2017 11:06 by David Higgs
posted: 8 Oct 2017 12:04

from:

David Higgs
 
Bletchley - United Kingdom

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Looking at the Moretonhampstead Photographs the Engine Release Crossover looks to be shorter than the NLS Maps.

posted: 9 Oct 2017 09:09

from:

David Higgs
 
Bletchley - United Kingdom

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Just had a quick dabble with the Engine Release Crossover, seems ok to me!
Attachment: attach_2518_3095_Moretonhampstead_Engine_Release.box     285

posted: 9 Oct 2017 09:10

from:

David Higgs
 
Bletchley - United Kingdom

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Uploaded background shape for Engine_Release
Attachment: attach_2519_3095_Engine_Release.sk81     292

posted: 11 Oct 2017 11:49

from:

David Higgs
 
Bletchley - United Kingdom

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How I can I make an adjustment to the Angle of the Diamond Crossing so that the "Main" Lines up correctly?
Attachment: attach_2527_3095_Moretonhampstead_BR(W).box     283

posted: 11 Oct 2017 11:51

from:

David Higgs
 
Bletchley - United Kingdom

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Background shape
Attachment: attach_2528_3095_Moretonhampstead_Site.sk81     389

posted: 11 Oct 2017 15:54

from:

David Higgs
 
Bletchley - United Kingdom

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I have made a few alterations but I'm still having problems getting everything "lined up", no doubt due to lack of understanding with Crossing Angles etc.
Regards

David
Attachment: attach_2529_3095_Moretonhampstead_001.zip     270

posted: 11 Oct 2017 16:41

from:

Martin Wynne
 
West Of The Severn - United Kingdom

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Hi David,

Thanks for putting the files in a .zip.

Your diamond-crossing is a mis-matched irregular diamond. It needs to be right-hand instead of left-hand and regular (all angles the same), I think probably 1:7.

Try creating it again, but this time have the main line as the control template, and the yard line as the background template. That will make it right-hand. After that it should be easy to create the turnout in the loop line using make ordinary crossover.

Just about to have some lunch, then I will have a closer look.

regards,

Martin.

posted: 12 Oct 2017 07:45

from:

David Higgs
 
Bletchley - United Kingdom

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Hello Martin,
Thank you for your reply, much appreciated.

Martin Wynne wrote:
Your diamond-crossing is a mis-matched irregular diamond. It needs to be right-hand instead of left-hand and regular (all angles the same), I think probably 1:7
I will follow your advice and modify my Plan accordingly.

There is just one question I'd like to ask and that is should the "V Crossing Angle" and the "K Crossing" Angle both be the same? I have altered the "V Crossing Angle" to 1:7 but haven't changed the "K Crossing Angle"; no errors were reported. Is this to do with Regular Angles Setting?

Regards

David

Edit: Just checked, both Angles are the same!
Last edited on 12 Oct 2017 10:30 by David Higgs
posted: 12 Oct 2017 08:37

from:

David Higgs
 
Bletchley - United Kingdom

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Ok, I've made the recommended alterations although I have an issue in that there is a difference in "Track Centres" at each end of the Loop. I started off with the Engine Release Crossover at 1:10 and at the other end of the loop I have used 1:7 to access the Goods Yard. The track Centres are wider at the beginning of the Loop.
Regards

David

Attachment: attach_2530_3095_Moretonhampstead_002.zip     256

posted: 12 Oct 2017 08:47

from:

Tony W
 
North Notts. - United Kingdom

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Hi David.
A regular diamond, by definition, has all the crossings at the same angle. It may be straight or curved, but if curved both roads will have the same radius.
Irregular diamonds have roads of differing radii or one straight and one curved, hence the crossing angles get progressively sharper through the diamond as the roads diverge.
Regards
Tony.

posted: 12 Oct 2017 09:35

from:

David Higgs
 
Bletchley - United Kingdom

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Hello Tony,
Thank you for your reply, much appreciated.

Tony W wrote:
Hi David.
A regular diamond, by definition, has all the crossings at the same angle. It may be straight or curved, but if curved both roads will have the same radius.
Irregular diamonds have roads of differing radii or one straight and one curved, hence the crossing angles get progressively sharper through the diamond as the roads diverge.
Regards
Tony.
I have a lot to learn with regards Templot and Trackwork although I'm quite enjoying the process. I'm a great believer in "learning by doing" and having a project is the best way to learn.

Thanks again for your help. 

By the way I liked the images of your Baseboards that you shared on the other thread. I was watching a DVD with Barry Norman talking about Plywood Baseboards and gleaned a few ideas so watch this space.

Regards

David
Last edited on 12 Oct 2017 09:55 by David Higgs
posted: 12 Oct 2017 11:42

from:

Martin Wynne
 
West Of The Severn - United Kingdom

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David Higgs wrote:
I have a lot to learn with regards Templot and Trackwork although I'm quite enjoying the process. I'm a great believer in "learning by doing" and having a project is the best way to learn.
Hi David,

Hmm. I persist in my belief that jumping straight in to aligning tracks over a background map is asking for grief. There is just so much that you need to know, which you can leave until later if you just want to learn Templot by creating layout track plans.

To start with, you are working in EM, so nothing is going to match exactly because all the lead lengths will be shorter. The better way is to design in P4, make a note of all the sizes*, then recreate the same in EM and decide for each template whether it is more important to match the crossing position or the toe position. You need to keep converting to CLM angles, because if you use the F5 function Templot will keep switching back to RAM. Most turnouts will need changing to generic crossings instead of the regular default.

Then you need some good prototype knowledge -- for example for a typical branch line such as this it is very likely that the switches will still be old loose-heel pre-grouping types, especially in goods yards and sidings.

None of that is too difficult once you know, but starting from scratch it is quite likely that the above is meaningless. And wouldn't be needed if you were designing a fictional branch terminus to practice the basic Templot functions.

But your track plan is mostly straights, so should be reasonably straightforward. :)

The key starting point seems to be the clearly marked toe position for the turnout across the diamond. By temporarily setting geometry > turnout road exit length to long, you can adjust the turnout size and crossing angle to match, and roam it along to match the toe position. The toe marks are shown on the templates (not the rail joints).

Like this: 

2_120557_100000000.png2_120557_100000000.png

That's in P4. The crossing angle for best match seems to be 1:7.1/4, which would be a very unlikely size for other companies but is listed as a standard size by the GWR. As you can see, that is with a 12ft old-type switch, generic crossing, and converted to CLM angle.

With that established, the next task is easy, tools > make ladder crossover > make regular ladder, and you have your diamond-crossing. You could maybe leave doing that until you have restarted in EM. Then tools > make branch track creates the track into the yard.

*or convert group on the gauge/scale dialog.

regards,

Martin.

posted: 12 Oct 2017 13:40

from:

David Higgs
 
Bletchley - United Kingdom

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Hello Martin,
Once again many thanks for your help, you must have the patience of a Saint. 

With your guidance I've now managed to achieve what I set out to do and that is to have all the Trackwork laid out on a scale map. I still need to do some refinements but this can take place as I gain more experience with Templot.

I know from being a Templot Forum Member for a number of years that you frown upon "jumping straight in to designing layouts".  I was spurred on to make some progress with my "Track Plan for Moretonhampstead" by the recent updates to the Templot Software in relation to "Importing Background Maps". I  have quite a few Photographs and Reference Books on Moretonhampstead and I also have the Great Western Study Groups "GWR Switch and Crossing Practice" by David Smith. I will take a look at them for further information.

I never set out to build an inch perfect representation of Moretonhamstead, I will have to apply some compression to fit the layout in the space available. I can now draw the Baseboards on the map and see where I can apply the compression and hopefully not detract too much from the prototype.

Regards

David

posted: 12 Oct 2017 15:53

from:

Tony W
 
North Notts. - United Kingdom

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David Higgs wrote:
Hello Tony,
Thank you for your reply, much appreciated.

By the way I liked the images of your Baseboards that you shared on the other thread. I was watching a DVD with Barry Norman talking about Plywood Baseboards and gleaned a few ideas so watch this space.

Regards

David
Funnily enough I was watching part of that video at our club meeting recently and thought that Barry made heavy weather of some of it. A band saw takes so much of the hard work out of cutting up the woodwork. Perhaps I should start my own thread.
Regards
Tony.

posted: 12 Oct 2017 16:14

from:

David Higgs
 
Bletchley - United Kingdom

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Tony W wrote:
Funnily enough I was watching part of that video at our club meeting recently and thought that Barry made heavy weather of some of it. A band saw takes so much of the hard work out of cutting up the woodwork. Perhaps I should start my own thread.
I thought the same, but I suppose (a) the video is a few years old now and (b) he shows that "Power Tools" are not essential but of course they make work and accuracy much easier.
Yes it would be nice a thread dedicated to Baseboards.

posted: 1 Aug 2018 15:13

from:

David Higgs
 
Bletchley - United Kingdom

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I have been doing a little research by reading the GWSG book "GWR Switch and Crossing Practice" By David Smith and also studying Photographs of Moretonhampstead during the period of interest, BR(W)1948 to 1958.
 
Guard Rails
The GWSG Book suggests that from 1910, Guard Rails on Crossings up to 1 in 7 ½ were 11' 6" in Length with 4 Check Chairs. Over 1 in 7 ¾ were 14' 0" in Length with 5 Check Chairs.

Studying Photographs of Moretonhampstead I found that most (if not all) Crossings had just 4 Chairs on the Guard Rail. To me, this would suggest that the Crossing Angles in use at Moretonhampstead were less than 1 in 7 ¾ . Certainly the Diamond Crossing when checked with Templot using an NLS Map as a Background shape, shows it to be 1 in 7 ¼  .
 
Engine Release Crossover
Comparing the 1936 and 1958 Maps from Old-Maps.co.uk shows a difference in the Length of the Turnouts. In 1936 the Turnouts appear to be much longer than the 1958 Map. The 1958 Map shows the Crossover begins near to the end of the Platform Slope. Photographs of the Station in the mid Fifties confirms the shorter length of the Crossing.
 
GWR 18ft straight switch and 1:10 CLM crossing looks right for the longer version whereas GWR 12ft straight switch and 1:7.25 CLM looks right for the shorter version.
 
Goods Shed Access Road
The Return Curve to the Goods Shed Access Road on both Maps is shown as running Parallel to the 'Main'. Photographs from the period of interest show a "Slew" in the Track, I assume that this so that a Locomotive can take on Water whilst standing on the Goods Shed Access Road, at the same time as keeping the “Main” Clear for the arrival and departure of the Auto Train.
 
 
Last edited on 15 Oct 2018 17:55 by David Higgs
posted: 15 Aug 2020 14:21

from:

Andrew Howlett
 
Torquay - United Kingdom

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Dear Martin,
Sometime ago you produced a template in P4 for the engine release crossover at Moretonhampstead using a 25inch OS map as the background template. 

The turnout details were 18ft heel switch (straight)
1 in 9.98 RAM (1 in 10.00 CLM)
adjacent track centres = 44.83mm

That equates to standard 6ft-way.

Unfortunately, Moretonhampstead was built to broad gauge. On conversion the platform road would have had the rail furthest from the platform slewed towards the platform by 27.75 inches and later standard gauge photographs indicate the loop road was narrowed in the same direction resulting in an increase to the "6ft-way" by that amount and a corresponding increase to the clearance between the loop and the inside of the train shed.

The 6ft-way shown on the OS map must, therefore, be wrong. If this is wrong it puts into question the geometry of the release crossover, and ultimately the accuracy of this and all other track plans.

Andrew Howlet

posted: 15 Aug 2020 15:28

from:

Martin Wynne
 
West Of The Severn - United Kingdom

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Andrew Howlett wrote:
The 6ft-way shown on the OS map must, therefore, be wrong. If this is wrong it puts into question the geometry of the release crossover, and ultimately the accuracy of this and all other track plans.
Hi Andrew,

I have moved your post to continue the existing topic.

I would be wary of assuming the OS map is wrong. The rails appear to be drawn at the correct scaled gauge, so it seems likely that the track spacing is also drawn correctly to scale.

The position of the release crossover has moved between the 1905 map and the 1936 map, which can only have resulted from a re-survey. It's not likely the OS surveyor would have recorded the position of a crossover without recording the track spacing.

The same thing happened again with the 1958 map -- the crossover has moved again but the track spacing still scales to 6ft way (although the maps on the old-maps.co.uk site are much poorer quality scans than NLS, and not geo-referenced or easy to establish the scale).

There is only one platform, so there is no obvious reason why the loop would need to remain at the older broad-gauge spacing when the gauge was changed.

However, a photo trumps a drawing, so if you have photographic evidence that the OS map is wrong it would be interesting to see the photos.

cheers,

Martin.

posted: 16 Aug 2020 10:49

from:

Andrew Howlett
 
Torquay - United Kingdom

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Martin,
Photograph M1 in Great Western Brach Line Termini by Paul Karau clearly shows that the 6ft-way in the vicinity of the engine release crossover is very similar to the length of one of the sleepers. The 6ft-way actually  looks too wide.
Would the map surveyors have bothered to measure the 6ft-way just assuming it was 6ft?

Andrew Howlett

posted: 16 Aug 2020 12:00

from:

Martin Wynne
 
West Of The Severn - United Kingdom

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Andrew Howlett wrote:
Martin,
Photograph M1 in Great Western Brach Line Termini by Paul Karau clearly shows that the 6ft-way in the vicinity of the engine release crossover is very similar to the length of one of the sleepers. The 6ft-way actually  looks too wide.
Would the map surveyors have bothered to measure the 6ft-way just assuming it was 6ft?
Hi Andrew,

There's no way of knowing precisely what an OS surveyor did in 1930, but whatever it was they seem to have done the same again in 1958. :)

I don't have that book, but I found this 1958 photo online:

moretonhampstead.jpg?w=768moretonhampstead.jpg?w=768
linked from http://chasewaterstuff.wordpress.com/2011/01/06/some-early-lines-the-moretonhampstead-and-south-devon-railway/

I will do some perspective correction on it and see what measurement the 6ft way seems to be.

It does at least clarify the position of the turnout at that time, and that it was an old-type loose-heel switch.

cheers,

Martin.

posted: 16 Aug 2020 12:38

from:

Andrew Howlett
 
Torquay - United Kingdom

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Hi Martin,
In the photo you are looking at, If there was a 6ft-way, then there would be a much larger gap between the loop and the train shed ; in the order of 7ft 11ins.

In broad gauge the distance from the platform edge to the inside of the far wall of the trainshed would have been 25ft 5.5ins - that is 2ft 1" + 7ft 0.25" + 6ft + 7ft 0.25" + 3ft 4ins.

In standard gauge you have 2ft 1" + 4ft 8.5in + 6ft + 4ft 8.5in = 17ft 6ins, leaving 7ft 11ins. There just isn't that sort of a gap.

One of your other correspondents has said that the slew in the goods shed road so that engines can reach the water crane (picture M38 dated 1955, in the same book) is not shown on the maps. This is another of the photographs where the 6ft-way looks wrong.

Andrew Howlett



posted: 16 Aug 2020 13:46

from:

Martin Wynne
 
West Of The Severn - United Kingdom

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Hi Andrew,

Clearly the spacing is wider than 6ft way in the photo I linked above, otherwise there wouldn't be room for the ground disc signal.

It's quite common for run-round loops to be wider than 6ft way, to allow for signal posts and staff on the ground.

Indeed, a strict reading of the rules requires it. Loops and sidings alongside a running line should be at 10ft way minimum, unless physical constraints prevent it. Which clearly a train shed might do. Whether a terminal platform counts as a running line is moot.

For GWR standard 6ft-0.1/2in way the space between the sleeper ends is 32.5in, i.e. approximately 3 sleeper widths and a bit. It is clearly more than that.

There are some more pictures on this page:

 http://www.disused-stations.org.uk/m/moretonhampstead/

cheers,

Martin.

posted: 16 Aug 2020 14:34

from:

Andrew Howlett
 
Torquay - United Kingdom

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Martin Wynne wrote:
Hi Martin, In a larger version of the photograph you posted, I compared the track gauge with the distance between the right-hand most rail and the inside of the train shed. Being straight-on there is minimum error. I measured a ratio of 17 to 20 which gives a distance of 5ft 6.5 inches, which compares pretty well with the theoretical 2ft 3.75ins + 3ft 4ins = 5ft 7.75ins.  It is likely, therefore that the 6ft-way measures in the order of 6ft + 2ft 3.75ins or 8ft 3.75ins. 
You have said that it is clearly more than 6ft because of there being room for the ground signal.
The maps show a 6ft-way of 6ft so I believe I have proven my statement that the Moretonhampstead 25" OS maps are wrong.

Andrew.
 
Hi Andrew,

Clearly the spacing is wider than 6ft way in the photo I linked above, otherwise there wouldn't be room for the ground disc signal


posted: 16 Aug 2020 19:37

from:

Martin Wynne
 
West Of The Severn - United Kingdom

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Hi Andrew,

Here is the 1886 map, which pre-dates the gauge conversion in 1892 and therefore shows the broad gauge tracks:

2_161430_020000000.jpg2_161430_020000000.jpg

The 7ft gauge is drawn very variably, but the track centres appear to be correct at 13ft-6in, assuming 3" wide rails and 6ft way between them (ignoring the odd 1/4" on the gauge).

So clearly at that time the OS surveyor did measure the actual spacing.

cheers,

Martin.

posted: 17 Aug 2020 10:18

from:

Andrew Howlett
 
Torquay - United Kingdom

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Hi Martin,
So we know the 1886 map is correct, but that the 1930 map is wrong. Assuming the surveyors correctly measured the toe positions of the turnouts which the cartographer correctly recorded, then either the surveyors did not measure the 6ft-way assuming it to be 6ft, or they did measure it and the cartographer ignored the measurement for the same reason.

Subsequent surveyors and cartographers merely recorded changes to the positions of the turnouts assuming the 6ft-way had not been changed.

If the turnout toes are in the correct places, but the gap between the platform road and the loop is in the order of 8ft 3.75ins rather than 6ft, then the crossing angles for the engine release crossover, the loop entry turnout, and the diamond crossing all need to be recalculated!

Luckily, my friend Mark who is building a model of Moretonhampstead hasn't quite got to the stage of laying the loop line.

Andrew.

posted: 17 Aug 2020 13:18

from:

Nigel Brown
 
 

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Is it simply a question of when the conversion from broad gauge took place then they simply slewed across the outer rail on both the platform and loop roads, leaving the nearer one in place, and that configuration held good ever after?

Nigel

posted: 17 Aug 2020 17:05

from:

Andrew Howlett
 
Torquay - United Kingdom

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Nigel Brown wrote:
Is it simply a question of when the conversion from broad gauge took place then they simply slewed across the outer rail on both the platform and loop roads, leaving the nearer one in place, and that configuration held good ever after?

Nigel
Hi Nigel,
That appears to be the case, but the map surveyors or cartographer did not take note of this and have mistakenly shown the 6ft-way to be 6ft as they expected, rather than show the 6ft-way as 8ft 3.75ins as it surely was.

Andrew

posted: 18 Aug 2020 08:59

from:

David Higgs
 
Bletchley - United Kingdom

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Surprised to see some recent activity on this thread!

I've modified my original Templot Plan of Moretonhampstead quite a lot after a lot of studying photographs and other research.

After a long discussion with a knowledgeable member of the GWSG my latest Plan shows the Platform Road to Engine Release Road to be 48.83mm Centres (12' 2 1/2").

Studying various Photographs shows the Engine Release Crossover to have two round Stretcher Bars and a single Heel Chair. They are 14ft, indicated by the seven SS slide chairs before the 1S heel chair.

GWR  14 ft. heel switch (curved) right-hand switch (joggled)
1 in 8.00 RAM ( 1 in 8.03 CLM ) generic V-crossing
square-on timbering
Last edited on 18 Aug 2020 09:01 by David Higgs
posted: 18 Aug 2020 09:37

from:

Martin Wynne
 
West Of The Severn - United Kingdom

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David Higgs wrote:
After a long discussion with a knowledgeable member of the GWSG my latest Plan shows the Platform Road to Engine Release Road to be 48.83mm Centres (12' 2 1/2").
Thanks David.

That makes the way 7ft-6in between the gauge faces (as measured by the GWR), i.e. exactly 1ft more than the usual GWR 6ft-6in.

The prototype designers were always more concerned with the way dimension than the track centres. I recently changed the dialog in Templot to make it easier to set the prototype way directly (adjusted for reduced gauges such as 00/EM).

But it doesn't allow for the GWR / BR(W) method of measuring to the gauge face, which adds an extra 1/2" to the way between the rails -- so for that it's still necessary to set the actual track centres. I will look at doing something about that.

When measured to the gauge face, the way dimension is often referred to in designs as the interval between tracks.

cheers,

Martin.

posted: 18 Aug 2020 10:23

from:

David Higgs
 
Bletchley - United Kingdom

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Martin Wynne wrote:
David Higgs wrote:
After a long discussion with a knowledgeable member of the GWSG my latest Plan shows the Platform Road to Engine Release Road to be 48.83mm Centres (12' 2 1/2").
Thanks David.

That makes the way 7ft-6in between the gauge faces (as measured by the GWR), i.e. exactly 1ft more than the usual GWR 6ft-6in.

The prototype designers were always more concerned with the way dimension than the track centres. I recently changed the dialog in Templot to make it easier to set the prototype way directly (adjusted for reduced gauges such as 00/EM).

But it doesn't allow for the GWR / BR(W) method of measuring to the gauge face, which adds an extra 1/2" to the way between the rails -- so for that it's still necessary to set the actual track centres. I will look at doing something about that.

When measured to the gauge face, the way dimension is often referred to in designs as the interval between tracks.

cheers,

Martin.
My contact did advise me of a deduced interval of 7'-6" so maybe I've used the wrong terminology? 
Last edited on 18 Aug 2020 10:26 by David Higgs


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