GWR 1:8 crossover puzzle

[West Junction]

Hi everybody, I have been enjoying reading other members postings and felt it was time to dip my toes in the hopefully warm water. I model very slowly in S7 with a preference for the Great Western steam era but also find 7mm diesels pretty impressive.
I have been using David J. Smiths GWR Switch and Crossing Practice book to try and get correct timbering for a GWR 1:8 crossover (6'.6" interval between tracks) but have come up with a problem regarding the centre line spacing between the timbers at the end of the vee legs. In table 9 page 147 he states that the vee legs in 1:8 crossover roads is 12'.0" which therefore requires a timber spacing of 2'.1" for the rail joint fishplates to be close to the chairs (page 83 second column line 11). Unfortunately this lines up with the spacing between the BC and 4C chair timbers in the adjoining road which require a timber spacing of 2'.7" (table 3 page 141).
I find it hard to believe that David's book is incorrect with the vee leg length but also cannot see anything wrong with my conclusion regarding the timber spacing anomaly. Can anybody tell me if my conclusion is incorrect? If it is correct the only answer I can come up with is to increase the length of the vee wings so that the rail joint at the end of the vees lines up between the BC and 2C chairs in the adjoining road as shown for the 1:7 crossover on page 86 (Fig.44).

 

[Heather Kay]

Welcome aboard one of the friendliest and most informative model railway forums around!

As you your question, I'm afraid I can't help. Someone will be along shortly who can, I will almost guarantee!

 

[40126]

.....As you your question, I'm afraid I can't help. Someone will be along shortly who can, I will almost guarantee!

Steve

 

[40126]

Welcome West Junction

Steve

 

[Simon]

When I had a similar conundrum with my C10 crossover, I think the conclusion was that the fishplate joints are staggered on the"crossover joint" in order to get a decent length of rail between the crossing nose and rail joint, I ended up butting up timbers together and then filling to suggest through timbering across both tracks.

Apologies if this answer is nothing to do with your question

I do have a copy of that mostexcellent book, but it's in the shed and I'm not

Simon

 

[Eastsidepilot]

I have no knowledge of GWR practice but I have some LNER info which may or may not help or just .....
This is how the LNER dealt with a 1-8 and some of the sleepering is extended to place chairs in the right position. Sometimes the joints were behind the checkrails.

ATB, Col.

 

[West Junction]

Thanks for the welcome and the trouble people have taken to reply, why didn't I think of posting a picture which makes it much more obvious where my problem is.
This is the 1:7 crossover illustration from David's book. The vee legs in this crossover are 12'.7 1/4" long putting the rail joint between the BC and 2C chairs in the adjoining road allowing the 2'.1" timber spacing. Obviously with a 1:8 crossover the points of the two vees will be further apart than with a 1:7 crossover and with shorter (12'.0") legs this brings the rail joints between the BC and 4C chairs in the adjoining road which require a timber spacing of 2'.7" not the 2'.1" required for the rail joint. If all else fails I will just extend the vee rail lengths so that the layout is similar to the 1:7 but this goes against David's 12'.0" leg requirement.

 

[Dog Star]

Now I can see your concern... what would happen if the splice rail length was extended to say 13'0"? A leg length of 13'0" instead of 12'0" would be a simple typo.

Looking at the diagram, there are crossing chairs at positions 1C, 2C, 4C and 5C so I suggest that the "BC" position is actually a blurred "3C". Given that the crossing nose is lying between 2C and 3C then I very much doubt that the sleeper spacing here is going to be anything other than 2'7" so that rather proscribes a rail joint in the adjacent line.

regards, Graham

 

[West Junction]

Hi Graham, The chair under the nose is definitely a BC chair as shown in the chair drawings Fig 48 of the book and is the only built up chair (BC?). David also refers to this 12'.0" vee leg on page 87 where he states "it will be seen that apart from the 1:8 crossing, all the vee leg lengths were either less than, or greater than, the standard dimension of 12'.0". " I am beginning to think that the only person who can answer this is the books author and I will have to use modellers licence and cheat by having a longer leg length.