• The Plug Track functions are experimental and still being developed. Some of the earlier pages of this topic are now out-of-date.

    Some pages of this topic include contributions from members who are creating and posting their own CAD designs for 3D printing and laser-cutting. Do not confuse them with Templot's own exported CAD files.

Tandem (3-way) turnout issues

James

Member
Location
Hampshire, UK
Good evening,

I am hoping someone may be kind enough to help.

I have attached the plan of Ropley (pre-preservation) with a map/picture I'm using to lay the track over (I hope I've attached the correct files to be able to see what I've been doing). I thought I'd made a reasonable stab at the plan and thought any issues with the 3-way turnout - that I always struggle with - I'd be able to resolve while making the turnout. This wasn't to be the case sadly and the turnout, although functional, did not align with the central track / siding coming off the turnout. This is meant to be straight (or very slightly curved) and this should continue through a straight central road in the tandem.

I can't work out how to adapt the turnout so it both aligns with all the tracks and is flowing / straight through the central road into the siding.

Would someone be able to have a look and tell me how to correct it if possible?

Many thanks in advance,

James
 

Attachments

  • IMG_5307.jpg
    IMG_5307.jpg
    1.6 MB · Views: 77
  • Ropley pre-preservation.box
    844.5 KB · Views: 45
  • Ropley pre-pres.bgs3
    12.4 MB · Views: 40
_______________
message ref: 3773
Location
Sandbach, Cheshire
Info
Builder of Finescale Signals in 2mm scale to 7mm scale, Trackwork, Turnouts and Layouts.
Part of the problem is that you are trying to match a prototype to 00-SF, so you are going to have a bit of a mismatch. I have altered the real plan size slightly and have made a start on the 3 way - you will just need to amend the timbering and put the sidings in and generally tidy up.
 

Attachments

  • market_square_2022_02_22_1031_53.box
    881.5 KB · Views: 36
  • market_square_22_02_22_1032_07.bgs3
    12.4 MB · Views: 33
_______________
message ref: 3781

Martin Wynne

Admin
Location
West of the Severn UK
Info
.
Enjoy using Templot?
Thanks.

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

Post your questions on the forum where everyone can see them and add
helpful replies.
@James

Hi James,

Welcome to Templot Club. :)

As Stephen says, using 00 gauge it is not possible to create a perfect match to prototype plans. But you can get close.

Also, you are using the REA bullhead switches which were invented in 1925, so would not be at Ropley in 1911 (or likely to be for many years afterwards). At that time they would most likely have been loose-heel straight switches. But using 00 makes it a bit academic, since neither will match exactly.

The first thing to look for is the positions of the switch toes, which are usually marked on maps. This is the position of the tips of the switch blades, not the stretcher bar:

james_tandem2.png


Your plan had the switch toes too far forward. For a tandem in 00 you are unlikely to get both switch toes to match, I started from the second one. Despite appearances, this is a single-sided tandem, both turnouts diverging to the left from the goods loop.

james_tandem3.png


I cropped your large image for faster screen response (crop/combine function), and applied Templot's map clarity improvement functions to make alignments a bit easier to see.

The tools > make tandem > single sided functions worked quite well, and this is the result:

james_tandem1.png


Files attached -- over to you to tidy up the timbering and possibly merge the check rails.

p.s. I changed the turnout in the running line to a C-9 for a better match to the plan.

cheers,

Martin.
 

Attachments

  • james_ropley.box
    691 KB · Views: 39
  • james_tandem_ropley.bgs3
    176.7 KB · Views: 40
_______________
message ref: 3784

James

Member
Thread starter
Location
Hampshire, UK
That is fantastic! Thanks so much to both of you for taking the time to look at this. The end result looks so much better than my attempt - I'm most grateful.

I've already got it printed off and stuck down ready for the fun bit. I'll post a photo of it completed - if it looks respectful enough!
 
_______________
message ref: 3790

James

Member
Thread starter
Location
Hampshire, UK
Sorry for a follow up question to something that I've already had assistance with but I've noticed a potential issue now Martin's version has been printed out. I've tried to show it in the attached photo.
IMG_6994.JPG

The issue that I'm worried about is that there's a potential jolt / sudden change of direction for a loco travelling down the central road because the right hand stock rail starts to curve before the second set of switch rails which means the train will start to turn right then jolt back left to a straight path when it gets to the switch blades.

Does that make sense and would that be an issue? Hopefully the photo explains it better!
 
_______________
message ref: 3796

James

Member
Thread starter
Location
Hampshire, UK
Thought I'd attach the most recent Box file for it. All I've done is shove timbers but I thought I'd upload it in case I've accidentally done something to Martin's hard work!
 

Attachments

  • Ropley after help.box
    514.9 KB · Views: 38
_______________
message ref: 3797

Martin Wynne

Admin
Location
West of the Severn UK
Info
.
Enjoy using Templot?
Thanks.

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

Post your questions on the forum where everyone can see them and add
helpful replies.
The issue that I'm worried about is that there's a potential jolt / sudden change of direction for a loco travelling down the central road because the right hand stock rail starts to curve before the second set of switch rails which means the train will start to turn right then jolt back left to a straight path when it gets to the switch blades.
@James

Hi James,

It's very likely that the goods loop was constructed first, and the sidings added later by inserting the tandem turnout in the loop. That makes it a single-sided tandem with both turnouts diverging to the left. The diverging turnout-side of a switch always involves a sudden change of direction at the deflection angle for the switch planing. For this reason switches in running lines always have a speed restriction over the diverging route.

In this case it is a very short siding to a dock, and it is unlikely that anything would move over the switch faster than walking pace. The effect of the switch deflection would be just the normal bumping and jostling of any shunting activity.

However, if you feel it should be a double-sided tandem from a dead straight middle road, I have re-done a design to achieve that:

james_straight_tandem.png


File attached below. Over to you to decide. Having a straight road certainly makes it easier to build. :)

It's not shown as a straight middle road on the map (yellow line is straight):

james_map.png


and I'm not sure even my first design included a sufficient S-curve in accessing the dock. The low-resolution of the scan makes it difficult to be sure. I will have a third go and see if I can achieve a better match to the map.

p.s. your photo shows a bug in the make tandem function related to the printed rail edges at the 2nd switch toe. Thanks for finding it, I will get it fixed.

cheers,

Martin.
 

Attachments

  • james_ropley_straight_tandem.box
    718 KB · Views: 39
_______________
message ref: 3798

James

Member
Thread starter
Location
Hampshire, UK
Hi Martin - thanks again for the time you've put into this - I'll have a look at the second attempt and have a think. However, your logic for the first attempt sounds more plausible so I may stick with this.

The bug is an interesting one (if we're both taking about the same one i.e. the switch rils look like they won't work! as this only appeared after I used the shove timber function. I printed off your first design with no changes and the switches look correct. After shove timbering and saving again to background, it changed (I'm guessing in an equivalent way to MS Word 'bringing to front'?)

So this may be user error on my part rather than a bug.

Thanks again for your help, I'll download V2 now...
 
_______________
message ref: 3799

James

Member
Thread starter
Location
Hampshire, UK
I've also been able to find one of the photos I'm using as reference that has been published elsewhere so isn't copyrighted which shows a slightly different arrangement to the map in that the central road seems to be pretty straight with little s-bend and on a very gentle constant curve -
ropley tandem.jpeg
 
_______________
message ref: 3800

Martin Wynne

Admin
Location
West of the Severn UK
Info
.
Enjoy using Templot?
Thanks.

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

Post your questions on the forum where everyone can see them and add
helpful replies.
Hi James,

That looks to be a later date than the 1911 map. It's possible the tandem had been renewed by then. It's part of the goods loop, so may have seen heavy use? The loop track looks well-used.

The run into the dock is significantly curved (yellow line is straight):

ropley_curve_dock.jpg


cheers,

Martin.
 
_______________
message ref: 3801

James

Member
Thread starter
Location
Hampshire, UK
Hi Martin, I've been lucky enough to have been in touch with the archivist for the Midhants Railway who has a wealth of knowledge and who thinks it is the same tandem / track layout as it was in 1911 but it was the map making side of things that was a bit 'dodgy'! His advice was to take the map with a 'pinch of salt'! The map was one drawn up for some building work so not an official OS map or similar so he thinks the accuracy of the map may not have been great and you're right, it's about 1933 when the photo was taken.

Apologies, I should have posted the photo along with the original post. Would it work for me to tweak the central road in your second attempt to have a constant radius to replicate the photo more (and slightly ignore the map?!)
 
_______________
message ref: 3802

Martin Wynne

Admin
Location
West of the Severn UK
Info
.
Enjoy using Templot?
Thanks.

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

Post your questions on the forum where everyone can see them and add
helpful replies.
@James

Hi James,

The map is marked "Surveyed September 1911" so I wouldn't dismiss it out of hand. It does match quite closely the 1896 and 1909 OS 25-inch maps:

ropley_25_inch.png


These all show what appears to be two separate turnouts rather than a tandem. Here I have matched the OS map as closely as possible. The turnout from the platform line is 18ft-11, the siding turnouts are both 12ft-6. This at 00-SF, but at scale gauge would likely be very similar sizes.

Clearly the photograph shows a tandem, so the track has been renewed since the 1911 survey. Do you have a later map? Unfortunately NLS don't have any later maps, and old-maps.co.uk has closed down.

cheers,

Martin.
 
_______________
message ref: 3803

James

Member
Thread starter
Location
Hampshire, UK
How interesting. Sadly I don't have any later maps and, although I have access to the MHR digital archive, there are no photos of the yard areas prior to the passing loop being lifted - which may well be when the tandem was installed to save space in the yard.

Decision time now then whether I go with the two separate turnouts or a tandem... the tandem appeals more from a track making perspective I think although I was keen to retain the passing loop for operational interest and it seems, to be accurate, it's one or the other!
 
_______________
message ref: 3804

James

Member
Thread starter
Location
Hampshire, UK
I am one and the same person as Rmweb ‘Harry’ so that’s my thread as well but focussed more on the research and prototype references rather than track (although there is a photo of my first attempt at the tandem). Oddly, the username James is one I used on Templot /85a for years and years but I had to re-register it recently but ‘James’ isn’t available on rmweb so I had to use my sons name ‘Harry’! Confusing but both me!!
 
_______________
message ref: 3806

Martin Wynne

Admin
Location
West of the Severn UK
Info
.
Enjoy using Templot?
Thanks.

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

Post your questions on the forum where everyone can see them and add
helpful replies.
@James

Hi James,

Looking at your topic on RMweb, it seems that you have already built what seems to be a very satisfactory tandem, so I'm not too clear what the problem is that you are trying to solve?

There was some obvious camera distortion in the photo you posted, so I have had a go at fixing it:

ropley_perspective_fixed.jpg


ropley_perspective_fixed1.jpg


There is a structure alongside the loop which your map has labelled a dock. It would be surprising if it was not dead straight, and all the maps show it as such. It follows that the track alongside it would also very likely be dead straight, and it does appear to be so in the photo (pink line):

ropley_perspective_fixed2.jpg


However, that line does not continue in alignment with the end dock siding, in the photo or on the maps. It's reasonable to conclude that the middle road must curve through the tandem into the end dock from the switch toe, and the straight yellow line does indicate that.

Reading your RMweb topic it seems that the layout was remodelled in 1931, so it is very likely that this tandem was installed at that time to replace the previous separate turnouts. In that case it is very possible that it would be using the REA switches.

Do you know the date of this photo from RMweb, is it before or after 1931? My guess is before -- was that the date when the opposite platform line was removed?

RP202.jpg.a8d944a9324535f5bafa5ec86f2a976f.jpg


There is a glimpse of the barrow crossing at the foot of the platform ramp crossing over the switch of the turnout. This means that the switch toe must be alongside the platform ramp, and not in front of the signal box as shown on the 1909 OS map. There is also a ground disc signal shown on your 1911 map, just to the west of the barrow crossing, which also usually indicates the position of a switch toe. Fixing the position of the switch toe affects the likely size of the turnout. The toe positions are often retained when remodelling a layout, to cause minimum disruption to the rodding runs.

cheers,

Martin.
 
_______________
message ref: 3808

James

Member
Thread starter
Location
Hampshire, UK
Hi Martin,

You are quite right - I have a reasonable looking tandem already made. It was one of those however, that as I made it I kept thinking "I wish I'd done it this way..." as it was the first tandem I have made. Although it doesn't show on the angles I photographed, the alignment is also out and I messed up the switch rails for the central road. It was one that my Mk1 bogie ran through really well while constructing but as soon as I tried the 4MT or S15 it was snagging all over so I resigned to redo it (that is the fun bit for me anyway so didn't mind really!)

Regarding the track layout / photos - I've gone back through the MHR archive I was sent and the notes that Keith (the archivist) provided. Sadly I can't share the images as they're copyrighted but I have emailed Keith this evening to see if I'm able to share one particularly interesting one.

What the photos show is that the 'up' line was removed in 1931 but nothing else was immediately relaid - therefore the 'down' line (closest to the yard) had a kink in it where the previous turnout joined it to the main up line. I have photos immediately before and after this and you're quite correct, the toe of the platform turnout is inline with the end of the platform - this was never altered as you say meaning I need to change this on my plan.

Equally interesting are the photos from 1950s which include the yard more clearly and show the, by then, relaid main line removing the kink mentioned earlier. It's very clear to see which elements have been relaid and which haven't by ballast colour etc. Interestingly, none of the yard has been relaid and Keith said he's pretty sure the yard retained the pre-war layout. The tandem is also clear to see in these photos and looks to be same age as the rest of the yard. If Keith gives permission, I'll post that photo as it gives real insight into the development of the pointwork. I think it means that if the tandem wasn't original and is a newer addition, it happened before the other track alterations in 1931 but after the map of 1911. It seems no-one knows if and when that happened though! Annoyingly there are no photos of the yard that show that section from pre-1930. (you're also right that the final photo above is before 1931 as you can see the 'up' line still intact on the far left although I'm not sure of the exact date).

I might just have to make an educated guess in the end for the layout!
 
_______________
message ref: 3809

Martin Wynne

Admin
Location
West of the Severn UK
Info
.
Enjoy using Templot?
Thanks.

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

Post your questions on the forum where everyone can see them and add
helpful replies.
@James

Hi James,

This my best guess at the tandem in the photo. 00-SF.

Double-sided tandem. The middle road is slightly curved through the tandem and then straight up to the end dock. The turnout in the platform road is C-10.

ropley_curved_tandem.png


File attached.

cheers,

Martin.
 

Attachments

  • james_ropley_curved_tandem.box
    137.7 KB · Views: 33
_______________
message ref: 3810
Top