Dog Star
Western Thunderer
This soul searching is all down to that S7 modeller of a GWR Edwardian "Bacon, Lettuce and Tomato" layout, Mr. Chris Brown (@ChrisBr) with Henley-in-Arden before 1908 (and the opening of the North Warwickshire line). All I did was to suggest that he had got the wrong style of GWR plain line chairs as the Exactoscale GWR 2-bolt chair was for the post 1900 "00" rail section whereas a closer to type chair was the C&L GWR 2-bolt chair for the GWR 95 rail section - given that the branch line terminus was built in the 1880s then the C&L chair is a better "fit" than the Exactoscale product.
OK, we got over that molehill and Chris has been doing some excellent work on a 3D-printed version of the GWR crossing nose chair from the Victorian-period given that the C&L slab and bracket alternative is too modern for a 19th century BLT. So I popped down to look at the samples recently, over coffee Chris talked about drawing / printing some of the other crossing chairs... I nodded in all of the appropriate pauses when a comment about L1 (Bridge) chairs struck with some force. Roughly put, Chris was quoting from the GWSG tome on GWR S&C Practice and saying that the L1 chair was not used prior to early 1930s, hence the need for a fair number of different block chair types for a common crossing. I agreed and then realised the significance of the statement.
Oh dear, whilst L1 chairs do get used for reasons of space in chairing a common crossing the L1 chairs also get used in other situations... for example:- to support rails alongside engine pits, for rails on longitudinal woodwork on steel bridges, where there is conflict between chairs adjacent to the joint between switch and closure rails.
So what did the GWR head-ganger do in the Victorian / Edwardian period before one of their number spotted the L1 chair in the stores inventory? Strange this, I had the answer without knowing the question; use narrow chairs fitted side-by-side on the same timber. Those of you who have been with me so far, and I mean back to round about page 11 of the story of Hartley Hill, ought to be saying something like: - "Oh yes, the GWR just copied the LNWR way of doing things" and that was to fit two (narrow) chairs side by side where standard chairs would not work.
A quick count up of how many such chairs in a typical LNWR turnout gave way to raised eye-brows - a couple of dozen chairs and producing such GWR "Z" chairs by reducing the width of C&L 2-bolt chairs with a 50% failure rate equates to a lot of sweat, swarf and failed attempts. To his credit Chris spotted the concern in my glazed eyes and suggested that maybe doing a 3D drawing of a z-chair ought to take precedence over further crossing chairs. Nice chap.
And now for the reason for this post!
Received wisdom for timbering of GWR turnouts is 14" under the crossing nose and switch toe with 12" under all of the other chairs in the formation. I have no reason to doubt this for post 1930s work where the L1 chair is in use. However, when considering the timbers for turnouts where the Z-chair is being used in "side-by-side" fashion for switch and closure rails close to the switch heel then the GWSG tome indicates that the GWR would have (ought to have) used 14" timbering (as per the LNWR for which I have copies of S&C drawings circa 1909 and those are marked for 14" timbers throughout a turnout). So Chris and I spent a couple of hours peering at images (spread across Warwickshire Railways where Z chairs are visible and Railway Archive websites) and have not done too well in identifying 14" timbers in the area of the switch heel. We can now spot the Z-chair in side-by-side use by looking for a chair which is significantly closer to one edge of the timber than the other - not so easy to decide if the timber, upon which a Z-chair is sitting off-centre, is 12" wide or 14" wide.
Anyone any information on use of 14" timbers within GWR S&C work of the period 1880 to 1910?
thanks, Graham
OK, we got over that molehill and Chris has been doing some excellent work on a 3D-printed version of the GWR crossing nose chair from the Victorian-period given that the C&L slab and bracket alternative is too modern for a 19th century BLT. So I popped down to look at the samples recently, over coffee Chris talked about drawing / printing some of the other crossing chairs... I nodded in all of the appropriate pauses when a comment about L1 (Bridge) chairs struck with some force. Roughly put, Chris was quoting from the GWSG tome on GWR S&C Practice and saying that the L1 chair was not used prior to early 1930s, hence the need for a fair number of different block chair types for a common crossing. I agreed and then realised the significance of the statement.
Oh dear, whilst L1 chairs do get used for reasons of space in chairing a common crossing the L1 chairs also get used in other situations... for example:- to support rails alongside engine pits, for rails on longitudinal woodwork on steel bridges, where there is conflict between chairs adjacent to the joint between switch and closure rails.
So what did the GWR head-ganger do in the Victorian / Edwardian period before one of their number spotted the L1 chair in the stores inventory? Strange this, I had the answer without knowing the question; use narrow chairs fitted side-by-side on the same timber. Those of you who have been with me so far, and I mean back to round about page 11 of the story of Hartley Hill, ought to be saying something like: - "Oh yes, the GWR just copied the LNWR way of doing things" and that was to fit two (narrow) chairs side by side where standard chairs would not work.
A quick count up of how many such chairs in a typical LNWR turnout gave way to raised eye-brows - a couple of dozen chairs and producing such GWR "Z" chairs by reducing the width of C&L 2-bolt chairs with a 50% failure rate equates to a lot of sweat, swarf and failed attempts. To his credit Chris spotted the concern in my glazed eyes and suggested that maybe doing a 3D drawing of a z-chair ought to take precedence over further crossing chairs. Nice chap.
And now for the reason for this post!
Received wisdom for timbering of GWR turnouts is 14" under the crossing nose and switch toe with 12" under all of the other chairs in the formation. I have no reason to doubt this for post 1930s work where the L1 chair is in use. However, when considering the timbers for turnouts where the Z-chair is being used in "side-by-side" fashion for switch and closure rails close to the switch heel then the GWSG tome indicates that the GWR would have (ought to have) used 14" timbering (as per the LNWR for which I have copies of S&C drawings circa 1909 and those are marked for 14" timbers throughout a turnout). So Chris and I spent a couple of hours peering at images (spread across Warwickshire Railways where Z chairs are visible and Railway Archive websites) and have not done too well in identifying 14" timbers in the area of the switch heel. We can now spot the Z-chair in side-by-side use by looking for a chair which is significantly closer to one edge of the timber than the other - not so easy to decide if the timber, upon which a Z-chair is sitting off-centre, is 12" wide or 14" wide.
Anyone any information on use of 14" timbers within GWR S&C work of the period 1880 to 1910?
thanks, Graham
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