Advice on building diamond crossings

[Barry Davis]

I have hand-drawn a double curved diamond crossing for use on my layout, as would be expected a ready made drawing was not available.

But unlike a double junction that I have just completed that had a 1:4 diamond crossing, this double diamond crossing has a pair of 1:2 diamond crossings.

I have not seen any photos of a 1:2 crossing in close-up and the photos of the real crossing are unclear, my question is with a diamond crossing of 1:2, should I bend or splice the outside rails and check rails. I am inclining to think that I should cut, file, and slice these rails together.

Barry Davis

[billbedford]

I have a plan of a LMS 1 in 2.5 diamond crossing which shows the wing rails on both the common and obtuse crossings to be bent to a 2 foot radius. An earlier LNWR drawing is similar but shows a bolt and spacing block at the apex of the crossings and a greater separation between the timbers at this point.

[grovenor-2685]

Here's one I made earlier, just a little experiment but I had no problem bending the wing rails.
Dimensions came from a Grant Lyon Eagre industrial turnout catalogue and it is 1:2.
One switch rail gone missing while it has been hanging around.
Regards
Keith

Ind-no2-2.jpg

Ind-no2-1.jpg

[Tim V]

My Grant Lyon catalogue gives spec down to 1:1.5 for 95lb Bullhead. No comment on the rails though.

[grovenor-2685]

Interesting, IIRC the 1:2 was the shortest turnout in the turnout table, there is a 1:1.5 crossing in the crossing table, the catalogue used to be on John Brighton's website but had been removed last time I looked. I downloaded some pages but apparently not the turnout table.
Martin Wynne has a slightly later version when GLE became part of British Steel and that also has 1:2 as the shortest turnout.

NB. A 9ft wb wagon will run round it but will buffer lock unless the loco has very wide buffers.
On DLR we have some shortened freightliner wagons for engineers use, the side buffers have been extended so they nearly meet in the middle and we still have to take great care on the 40m radius crossovers.

This can be helpful http://www.norgrove.me.uk/GWRtracknotes/R1774A.pdf
Regards
Keith

[John McAleely]

be helpful http://www.norgrove.me.uk/GWRtracknotes/R1774A.pdf

FYI, these also appear to be on this website, here:

www.scalefour.org/resources/gwrtracknotes

[Martin Wynne]

I have hand-drawn a double curved diamond crossing for use on my layout, as would be expected a ready made drawing was not available.
But unlike a double junction that I have just completed that had a 1:4 diamond crossing, this double diamond crossing has a pair of 1:2 diamond crossings.

Hi Barry,

A construction template for a 1:2 curved diamond-crossing could have been printed with just a few clicks from Templot (it's free to use). For both regular (similar radii) and irregular (radii differ) forms.

You would still need some prototype details. Here is part of a scan from the NERA reprint (1:2):

half_diamond2_scan_cropped.png

The full hi-res page scan with constructional details is here (14MB): http://templot.com/forum_img/half_diamond2_scan.png

From the drawing you can see that the wing rails for both the K-crossing and te V-crossing are bent at 1ft-6in radius.

regards,

Martin.

[Barry Davis]

Hi Guys,

Thank you very much for your advice. The LNER drawing of Common and Obtuse Angle 1in2 crossing was most helpful.

Looks like I will be bending the running rails and check rails.

Attached are a couple of photos of the diamond crossings drawing in position on my layout prior to me starting work on constructing them.

Thanks again every one

Regards

Barry

[grovenor-2685]

Looking good that, rather reminds me of the South end of Derby. http://www.norgrove.me.uk/signalling/plans/Derby.gif If that is a goods line crossing don't forget it needs traps both sides.
Regards
Keith

[martinm]

K?eith,
both Derby and Trent images won't display?
martin

[grovenor-2685]

K?eith,
both Derby and Trent images won't display?
martin

They do for me, maybe you are short on memory, I can't make the images smaller or they would be illegible, but I'll check when I get home in case the colour depth can be reduced.
Keith

[Martin Wynne]

Hi Martin,

The image is 25,316 pixels wide, so may not display in a browser (ok here in Firefox, with much sideways scrolling).

If not for you, right-click on the link and then Save Link As...

Then open it in a graphics editor program such as Microsoft Paint, PaintShopPro or Irfanview (free).

regards,

Martin.

[Barry Davis]

Hi Keith,

Sorry nothing as grand as Derby. This is the track formation at the west end of Barnham station on the LBSCR's West Coast line from Brighton to Portsmouth.

The line crossing it is the double track branch line to Bognor Regis. I can't see any trap points in all the photos that I have accumulated, and that could be because of the close proximity of the 750V third rail.

Regards

Barry

[martinm]

(ok here in Firefox, with much sideways scrolling).
If not for you, right-click on the link and then Save Link As...
Then open it in a graphics editor program such as Microsoft Paint, PaintShopPro or Irfanview (free).
regards,
Martin.

Thanks, Martin,

I am using Firefox, so rarely have problems. Was concerned when it seemed that it was just these two.

Still don't know, but 'save as' did the trick

regards,

martin

[grovenor-2685]

Sorry nothing as grand as Derby. This is the track formation at the west end of Barnham station on the LBSCR's West Coast line from Brighton to Portsmouth.

The line crossing it is the double track branch line to Bognor Regis. I can't see any trap points in all the photos that I have accumulated, and that could be because of the close proximity of the 750V third rail.

Google maps shows most of the layout still extant, and the position of the platforms reveals the line across the diamonds as a passenger line anyway so traps not needed.
Nice to see the old P4 templates in use after all these years.
Regards
Keith

[Terry Bendall]

This is the track formation at the west end of Barnham station on the LBSCR's West Coast line from Brighton to Portsmouth.

What period is the layout Barry?

Terry Bendall

[JFS]

This is the track formation at the west end of Barnham station on the LBSCR's West Coast line from Brighton to Portsmouth.
I can't see any trap points in all the photos that I have accumulated, and that could be because of the close proximity of the 750V third rail.

Hello Barry,

I thought I recognised it - I knew Barnham well in my misspent youth! No traps are needed as the layout is "self trapping" and there are no Goods only lines. There was, of course, I trap at the exit from the Engine Siding worked by lever 68 Unfortunately the layout was chopped about 5 years ago when the signal box was closed.

If you are interested in how the layout was worked, you might be interested in my signal box simulation:-

http://www.blockpostsoftware.co.uk/downloads.php

which is set in the late sixties / early seventies.though it must have been even more interesting pre-electrification!

Very much looking forward to seeing progress!

Best Wishes,

[Barry Davis]

Google maps shows most of the layout still extant, and the position of the platforms reveals the line across the diamonds as a passenger line anyway so traps not needed.
Nice to see the old P4 templates in use after all these years.
Regards
Keith[/quote]

Hi Keith

Years ago I purchased most of the original P4 templates. Over years these P4 templates have been photocopied, cut, bent, and joined to make other turn out formations, in fact the P4 template on the left started out as a TT/B6L-B8L, but I am using it as a template for a curved turnout. After your comment about trap points, the only trap point that I can find is from the exit from the two 12 car berthing sidings along side the loop platform\, which I believe have now been removed.

Regards

Barry

[Barry Davis]

What period is the layout Barry?

Terry Bendall[/quote]

Hi Terry.

When I planned my layout it was going to be a modern image Southern Region layout in the early 1960's. I first discovered P4 after reading the then Model Railway Constructor, which made me decide to scrap all my OO ideas and started again in P4. Then I got married, then my wife and I saved up for our first house, followed by my wife and I starting a family. Now after many years, my wife and I have three grown up daughters, a nice home, and I have some free time left to spend on completing my layout, and adding the all important southern out-side third rail.

It is now many years from my original concept of a modern Image layout, and my Southern Region layout has now turned into an historical layout based on Barnham Junction circa 1960, and due to limited space that I have available, I have condensed it by about a third to fit into the 26 foot by 11 foot integral garage.

When I first stated building Barnham I wired it up using Gauemaster DC controllers, but I found that it was so limiting to what I wanted to do and I could not realistically operate on my layout.

One big advantage of completing my layout in later years was that it allowed me to scrap literally miles of obsolete DC wiring and controls, and convert to my layout, locomotives and EMU's to simplicity of the then new DCC.

For example, at Barnham, the down Victoria - Bogor Regis - Portsmouth Harbour service uses three 4 car emu's which split at Barnham, eight cars carry on to Portsmouth Harbour and the remaining four cars which included the buffet car went to Bognor Regis. And every hour the corresponding up service from Portsmouth Harbour and Bognor Regis to Victoria would re-join at Barnham. I could never replicate these and other workings, and operate Barnham realistically to a 1955 BR Southern Region timetable without the fine control of DCC. On my model, because I have condensed Barnham by a third, I am limited to eight car emu's trains, and seven coach steam locomotive hauled trains.

So that briefly is my layout Terry

Regards

Barry