Gwr Track Chairs

[28ten]

Thinking about it this afternoon it will be very hard to hold the rail at the correct inclination and maintain gauge without the integral keys. The only way I could see is to do the sleepers and chairs as one print/casting similar to Grahams suggestion, but that would make wooden sleepers impractical. There will be nothing going off until after the New year so I have time to think.....

 

[Dog Star]

Well, if there are no takers for Rocket Precision then time for another blast from the past.... and one which might be a solution to the problem of gauging 3D-print chairs without keys. In the good old days, when the trade pages were green (or some other nonchalant colour), the worthy Model Railway Constructor carried adverts for Allen Brett Cannon of London Bridge (ABC to all and sundry). Amongst the many desirable nits and pieces which could be bought from the emporium there were cast chairs for 4mmscale BH rail - and those chairs were cast with a spigot.

Given the accuracy which is possible in the drafting design and subsequent 3D printing processes then, provided that a suitable drilling jig is made, including a spigot to the underneath of a chair will enable accurate and repeatable construction of track with wooden sleepers. A second drilling jig will enable accurate gauge widening for those kitchen-table curves.

regards, Graham

 

[28ten]

I have worked out a better way of modelling the chair, it just needs fillets, bosses and some decals.
It wont be too painful to do a test with and without keys, there is always the possibility of putting a spigot under the chair and lasering the sleepers to gauge the track. As a one off for a small layout diorama it might just be practical

 

[Dog Star]

As you seem to be using the GWR chair drawing and photos from the references which I provided earlier in this thread I hope that you do not mind a word or two of caution. I am satisfied that the drawing is accurate and provides information about a chair which was widely used by the GWR circa 1890s. The photograph seems to be of a chair which corresponds to the GWR drawing... where I council caution is in the way in which the prototype chair has been "marked". The GWR pattern shop would have put metal letters/numbers on the original wooden pattern and those markings would have been incorporated into the resulting metal pattern as letters and numbers proud of the surface. The photograph shows that at some time the letters and numbers have been ground off of the metal pattern with new identification added to the metal pattern by chisel / gouge / grinder. All of this suggests that circa 1890-1900 the GWR was out-sourcing casting and subsequently bought the patterns in-house (as is explained in other related posts to the Basilica Fields journal regarding the 1885 (or earlier) chair which was cast by McKenzie and Holland).

regards, Graham

 

[28ten]

Point taken, I need to go and have a look at some more chairs. An older pattern would be more appropriate for what I want, as it wouldnt have been relaid with new track, further examination of photos is needed, but I am happy I can draw a decent representation of the prototype which is first base, and it wouldnt take long to draw any variations.

Edit - Looking at your other pictures on the blog the chairs you have been using are more like the one in Rices book. Of course I could always mix them up a bit

 

[Dog Star]

I need to go and have a look at some more chairs.

I suggest that you start with the Barry Island web site.... the track is laid with 85/ 95 lb rail and the chairs are very suspiciously like the one which you are drawing at this time.... look at the "corners" of the chairs, rounded rather than square as per the "00" section chairs of 1900 onwards.

Fun is it not? Laser brickwork might be simpler.

 

[Dog Star]

Looking at your other pictures on the blog the chairs you have been using are more like the one in Rices book.

Please point me at the photos which you are referring to in the quote... and can you offer the relevant photo in Rice? (fair use and research justification).

regards, Graham

 

[28ten]

I suggest that you start with the Barry Island web site.... the track is laid with 85/ 95 lb rail and the chairs are very suspiciously like the one which you are drawing at this time.... look at the "corners" of the chairs, rounded rather than square as per the "00" section chairs of 1900 onwards.

Fun is it not? Laser brickwork might be simpler.

I was searching chairs and the Barry Island site popped up I must admit it is a can of worms, I just found about oo rail this afternoon when i dusted off 'Switch and crossing practice' If you have GWJR 44 there is a shot on p190 of the patterns for the chairs.

 

[Dog Star]

I must admit it is a can of worms, I just found about oo rail this afternoon when i dusted off 'Switch and crossing practice'.

You telling me???? Tell me!!!! !!!!! !!!!! The "GWR S&C Practice" book (David Smith, GWSG) covers PW and S&C through the twentieth century and hardly touches the designs and practices which came through from the Dean era - and yet such rail / chair/ sleeper materials could still be found to the demise of the traditional goods yard. I had cause to talk to David Smith about an aspect of sleeper arrangements and in that conversation he offered an opinion that there was little in print about GWR track to pre-"00" standards (called the nought-nought section from the year of introduction). I have provided references in the Basilica Fields journal for all that I have found after talking to relevant specialists (including some who worked in the appropriate GWR / BR-WR offices).

regards, Graham

 

[28ten]

It is official I have become a chair spotter
For those curious, this is how I go about the modelling, (an ordinary chair in this case) as there are lots of freehand curves I creats 3 planes and scale my drawings to known dimensions and work from that. so far there are 3 primitive shapes and 3 cuts with lots of little curves yet to be added.

 

[Dan Randall]

Nice work on the chairs Cynric. What software are you using please?


Regards

Dan

 

[28ten]

Inventor, but Alibre would work just as well, the basic techniques are the same.

 

[Dog Star]

Your image of a 3D chair with the corresponding projection views from a drawing suggest to me that you are drawing a chair for 00 section rail - I think that rail weight and the corresponding chair might be too modern for a branch line with a low axle loading. The discussions on your layout / diorama / cameo thread have indicated that your intentions are for a branch such as Wallingford.... there ought to be enough photos of that line to determine which type of chair is the more appropriate (as in Rice or as in Harvie).

regards, Graham

 

[28ten]

Your image of a 3D chair with the corresponding projection views from a drawing suggest to me that you are drawing a chair for 00 section rail - I think that rail weight and the corresponding chair might be too modern for a branch line with a low axle loading. The discussions on your layout / diorama / cameo thread have indicated that your intentions are for a branch such as Wallingford.... there ought to be enough photos of that line to determine which type of chair is the more appropriate (as in Rice or as in Harvie).

regards, Graham

It is indeed an oo chair, but I will do the older chair as well. It is all drawing practice
I will be using Cliff Barkers rail http://www.cliffbarker.talktalk.net/finescaletrackdevelopement.html which is code 180.

 

[Dan Randall]

Nice work on the chairs Cynric. What software are you using please?

Inventor, but Alibre would work just as well, the basic techniques are the same.

Thanks Cynric.


Regards

Dan

 

[iploffy]

Cynric have spoken to my mate at Oxley and he said there are some 1900-1910 GWR chairs in the yard. He will take loads of pictures and then give me a memory stick with them on to post on here. An interesting note when the new office block was being built 2 years ago they in earthed some of the original rail laid when the yard was first opened as goods sdgs, when the contractor was told their exact words where we have not got time to dig it up and then they proceeded to cover it in concrete what a waste

Ian

 

[28ten]

Thanks Ian

 

[iploffy]

Cynric I have not forgotten I should have the memory stick sometime this week as for the loose chairs he went hunting for them and the contractors have removed all of the loose ones when they re-signaled Oxley last year

 

[28ten]

Cynric I have not forgotten I should have the memory stick sometime this week as for the loose chairs he went hunting for them and the contractors have removed all of the loose ones when they re-signaled Oxley last year

Thanks Ian. That means they went to scrap