GREAT WESTERN ECHO

26 AUTUMN 2015 211 211 AUTUMN 2015 27

GREAT WESTERN ECHO

n September 1955 Ken Cook (sometime Principal Assistant to F W Hawksworth and later Mechanical and Electrical Engineer of the Western Region, subsequently Chief Mechanical and Electrical

Engineer, Eastern and North Eastern Regions) became President of the Institution of Locomotive Engineers and gave a presidential address whose title I have borrowed for this article. For me that paper represents something of a milestone in railway technical literature as it not only revealed some of the precision production practices within Swindon (which were usually not shared) but it did so to the very audience that the GWR had all but snubbed for many years previously. Swindon engines were known to be built to closer tolerances than other railways and ran significantly greater distances between shop visits as a result - but how they achieved that was something of a secret. As the Night Owl project prepares for horn alignment and re-wheeling I revisited the Cook paper looking for a technique we could replicate and achieve the Swindon close tolerances. I knew they had a huge mainframe jig that could grind all loco horns in the one setting but this was clearly not appropriate for our job. Then I noticed a small photograph in the paper. This was a mobile jig that was used to true up a single horn face as a quick repair. This faded image became the starting point of the 4709 Horn Grinding Machine and after almost a year of development we have produced a machine that can effectively grind

IThe Steam Locomotive: a Machine of PrecisionPAUL CARPENTER BRINGS US UP TO DATE ON STEADY PROGRESS WITH ‘NIGHT OWL’ 4709

the four faces of one axle in a single set-up to Swindon tolerances. This has been quite a voyage of discovery we have received a lot of help on the journey. Bob Meanley at Tyseley has long since appreciated the value of such a tool and he was kind enough to show me his set up when he worked on the ‘County’ mainframes. We haven’t copied his or anyone else’s machine, but it was helpful to discuss aspects of the design and challenges encountered. We have also had help from many other sources but I must thank Colin Driver who patiently produced drawings for eight revisions of our machine (!) and Dave Ham whose machining

expertise has produced a device that is capable of working to very close tolerances. It is hoped that this piece of equipment will help other projects to get this critical alignment right and also generate funds for 4709. The Night Owl project has been quietly progressing on several fronts recently. Our Resident Engineer Don Ashton is ever busy designing and producing CAD drawings to allow manufacture of parts for which works drawings have not survived. This is tricky work and requires a thorough understanding of the mind of the 1920s Swindon Design Engineer. We are planning to show his work on a new section of the website which will make interesting viewing. Recently Elliot Powick joined the team and has been producing 3D versions of 4709 parts. This is ‘state of the art’ technology and allows us to ensure that parts fit together straight off the board. Again we will

Above The Swindon photo from Ken Cook’s paper that provided inspiration for our own horn grinding machine.Top Even in its final days, the majesty of Churchward 47XX Class 2-8-0 No. 4703 is radiant in one of the roundhouse bays at Old Oak Common on Sunday 3 May 1964 - a precision machine, built to last. On the left is 4082 Windsor Castle, while in the background lurk two Class 52 ‘Western’ diesel hydraulics, which in little more than a decade would themselves be history. Geoff Plumb

One of Don Ashton’s worksheets for the brake gear on 4709 exemplifies the quality of work being carried out on development of the project.

be showing these assembly drawings on the website and they will reflect the current stage of the engine. Richard Croucher and I have been working for almost a year to procure a fourth axle and ten new tyres for 4709 at the right price. We made enquiries as far afield as Germany, China and USA before agreeing a contract with the Wheel Set and Brake Company in Derby. Although this has taken time we have been able to achieve significant reductions in the cost of the forgings and these are now on order. They will be delivered early in 2016 and form an important next step towards wheeling the loco. Work at Llangollen has also been progressing, the extension frames now having been completed and the extension frames are imminent. Once completed, they will be permanently fitted to the mainframes and reveal for the first time the huge and majestic size of the Night Owl. We will then grind the horns and fit the axleboxes ready for wheeling. Axlebox overhaul follows accepted practice, except that these are donations from other classes. Sometimes there are nasty little addenda to upset the apple cart and the main drawing may not be specific. On one occasion two holes in a casting clearly sported a dimension of 5in, but an added remark, ‘4.5in on Class 47’, was a physical impossibility. The Brakes Worksheet is a preliminary design sheet on which to sort out missing information and test out veracity. Scouring drawings of other close items, hunting through our generous library of photographs (thank you kind donors) and having regard to the proposed duties of 4709 may suggest a small refinement or a change in principle. The worksheet showed up the original problem areas, points of suspected changes and finally allowed considerable use of parts rescued from 2861. The ongoing major challenge is funding and it controls our rate of progress. If you would like to see 4709 on its wheels, now would be a good time to come forward. Help could be in the form of a monthly contribution – every little helps – or perhaps consider sponsoring a part. Recently we have been very fortunate with two companies prepared to sponsor scopes of work. The first is CoMech who have generously offered to undertake the UAT tests on the donor axles – Thank you Keith and team. Chris Watson of Watson Abrasives is an expert on grinding processes has been very

helpful with the Horn Grinding Machine and has offered to sponsor the grinding wheels – Thanks Chris. Such sponsorship really helps us move the project forward so please consider helping in this way – it doesn’t have to be large sums of money – although these

move progress even quicker! With such support 2016 should to be a significant year for 4709. Unfortunately in 2015 we lost one of our true allies – Bob Fry. He was a real supporter of our project and went to extraordinary lengths to help us. Earlier this year he sourced all the exhibits for the Night Owl stand at the London Model Engineering Exhibition. This is a

three day show and he willingly supported our team in manning the stand. Together with Richard, Bob and I would regularly meet in London to plan the next steps for 4709. He had a real ‘can do mentality’ and was always encouraging in his friendly and affable way. He will be greatly missed.

We have been invited to present a display for our engine at the London Show again in January next year and new members of the stand team would be very welcome. In an effort to attract funding we are keen to learn more about the freight activities of the 47XX class, especially in the years after the first world war but also throughout their long lives. Please share with us what you saw, what you know, or what you did with 47xx freight trains. On 28 September this year, Richard Croucher and I gave a presentation entitled ‘Return of the Night Owl’ to the Railway Division of the Institution of Mechanical Engineers. This is the current form of the Institution of Locomotive Engineers and hence the same audience that Mr. Cook addressed sixty years ago almost to the day – truly the return of the steam locomotive to the Institution. They are proud to be associated with our project and are keen to assist us in delivering

this fine example of British manufacturing and the final masterpiece of G J Churchward. We welcome volunteers to help with all aspects of the ‘Night Owl’ project, especially hands-on engineers, marketing and sales people. Please contact me, by email at pcarpenter100@btinternet.com if you would like to become involved and support us. For offers of financial support please contact Richard Croucher, chairman@didcotrailwaycentre.org.uk, or phone 01235 817200.

When the extension framehas been joined to the mainframewe shall be at this stage...

Acquisition of tyres, crankpins and springs will enable us to move to this stage!