An O Gauge layout based on the now closed branch line terminus at Ashburton in Devon

Built and described by Paul Plowman

Initial Thoughts

Above: Former GWR Autocoach W38 by Dapol

Over the past year or so it has gradually become apparent that I need to seriously review the future of my Littlehempston P4 layout. Age is catching up with me and realistically I will probably have to down size into a smaller property or retirement accomodation within the next five years. An assessment of the tasks outstanding to complete the layout suggest that completion is unlikely to be achievable within the five years. I am therefore faced with the question, do I continue to spend money, time and effort on a layout which will probably have to be broken up before it is completed? There is little chance of the layout coming with me as it will need at least a 3-car garage to accomodate it which would be a very unrealistic expectation. My thoughts are that I should now abandon the project or at least cut back on it and direct my efforts towards building a new smaller layout which could, at least in part be erected in a single unit garage in the future.

About 35 years ago when I was working in the CCE's New Works Office of Southern Region a student came into the office with a 40ft - 1in scale plan of Ashburton which he had acquired from the records office at Swindon. I managed to persuade him to loan the plan to me for a few days while I spent my lunch times tracing it on to linen. Many years later I digitised the plan to enable me to load it into a CAD system. The resulting computer model is probably not that accurate but it is the best I can expect.

In CAD I rescaled the survey to 7mm to 1 foot. Here in Australia it is usual for houses to have what is called a "rumpus" room. It is a extra living room and is used for a variety of purposes, television room, music room, games room, gym, etc. When I overlayed the 7mm scale survey of Ashburton over an outline of the room I found that I could fit the layout from the buffer stops to the engine shed inclusive and close the room off from the adjacent main open plan living area. The Malthouse would need to be on a seperate removable baseboard extending into the living area. At a future date the section between the buffers and the engine shed could at least be erected in a single garage unit although operation would be difficult.

As a subject for modelling Ashburton has a lot going for it. Firstly there are a huge number of photographs on the internet and in books. In addition the excellent book "Great Western Branch Line Termini" by Paul Karau contains pull out drawings of all the main buildings including the overall roof. These three main buildings still exist, although somewhat modified and can quickly be found with Google Earth and Streetview.

The one problem I have come up against is that the survey from which I am working is dated 1914. The layout was altered around 1930 to extend the loop. Prior to remodelling it was only possible to run round two coaches. The extended loop made it possible to run round 4 Mk1 coaches or 5 coaches of around 57ft. However, the reason for extending the loop was probably more to do with the length of cattle trains rather than passenger trains. In later years the service was provided by a loco and single coach, either an autocoach or finally a single non-corridor brake composite. At busy times the formation might be increased to two coaches. With CAD using the 1914 survey as a background I have had to redesign the layout in its later form from photographs. I say 'redesign' because other than the release crossover every turnout appears to have been moved and none of them are straight. Fortunatey details of Great Western turnouts can be found in publications from the Permanent Way Institution.

Above: CAD Design

In undertaking this redesign process a number of interesting features were revealed. Firstly it appears that the layout was just built with anything second hand that was available. There is no other reason for the release crossover to be made from two B8.25 turnouts. It also appears that the turnouts were very cleverly positioned to suit the alignment of the running line. This layout cannot be built using proprietry turnouts. Peco turnouts are completely unsuitable for anything other than use in the hidden sidings. I will have to build all six visible turnouts from stratch.

My chosen period is the early 1950's when auto working was still in operation and the autocoaches could be seen in a mixture of red and cream or all maroon liveries. Only two classes of locomotives were used on the Ashburton Branch, the 14xx Class 0-4-2T and the 45xx Class 2-6-2T small praire. Both of these classes are available from Dapol. Usually the goods was worked by a 45xx praire but one of these locos was later withdrawn and replaced by a 16xx Class 0-6-0PT. Unfortunately a ready to run model of this class is not available. Dapol make a 64xx Class 0-6-0PT but these did not appear on the line until the preservation era. Auto coaches are also available from Dapol and so far I have purchased W37 and W38.

Above: Former GWR Autocoach W37W by Dapol

A major decision which has to be made at an early stage is the method of track construction. 47 years ago I started building an O Gauge layout, yes it was 47 years ago! Unfortunately we needed to make a household move. Our new house was not suited to O Gauge and I continued working with OO. However, some progress had been made with the construction of a tandem turnout and two crossovers. The concept was that building pointwork in easy to manage modules would be better than leaning over wide baseboards to build pointwork in situ. The materials used are all Peco, comprising rails, S1 chairs and slide chairs. It was quickly realised that the Peco plastic chairs were not going to be suitable or strong enough to hold critical components in place, such as flexible switch blades. It was also desireable to have a layer of sound absorbing material under the track to prevent vibration being transmitted to the main baseboards. The choice was for a sandwich of half inch wood fibre insulation board topped with 3mm plywood. The plywood would provide a firm surface to hold small brass screws to which the critical components could be soldered. It would also be a suitable surface to hold track pins. The wood fibre insulation board would absorb sound while screws and pins could protrude slightly through the plywood.

Above: Pointwork built for a previous project showing plywood sub-base laid on wood fibre insulation board

The sleepers and timbers are balsawood. Balsawood might seem rather soft for this application but it can easily be cut with a sharp knife and readily aborbs wood stain. This method of track construction has not been tested with the pounding of heavy O Gauge locomotives so it needs to be given some thought.

Above: This image shows the realistic effect of balsawood timbers

Above: Pointwork built for a previous project

I have made the decision to continue with this method but to use cork floor tiles as a sub-base instead of wood fibre insulation board. At the time of writing I have not made a decision about the use of balsawood timbers. A possible alternative would be plywood.

Paul Plowman
17 February 2020

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