Model Engineer

Polly Model Engineering Few of us, I imagine, are unaware that Andy and Jane Clarke have recently retired from Polly Model Engineering and that the supplier has now moved into the care of new management. I would like to wish Jane and Andy a happy and productive retirement, as well as Prof. Pete Thomas, who retired from Polly a little while ago. Pete has sent me a press release detailing the changes to the company, as below. ‘AT Model Engineering Limited is pleased to announce the acquisition of the business and assets of Polly Model Engineering Limited on the retirement of directors Andy and Jayne Clarke. The new business will continue to trade as Polly Model Engineering, from new premises in Cromford Derbyshire. ‘The company will provide a comprehensive range…

OSCILLATOR The history of swinging-cylinder engines is a long one. No less an engineer than I.K. Brunel used oscillating machines to power the huge paddle wheels of his Great Eastern (above), while thousands of toy steam models have employed the same principle. Such engines are simple in design, easy to make and will run for long periods with minimal attention. The downside is that the oscillator's efficiency in its usual model form is less than ideal. Indeed, the father of model engineering, Henry Greenly, wrote ‘Advance in the timing of the units is impossible’. The problem is inherent in having the timing of the inlet and exhaust controlled entirely by the side-to-side motion of the cylinder. This is at once the oscilllator's strength and its weakness. Nonetheless, for those planning…

Continued from p.383 M.E.4712 March 10 Astalwart group from the Uckfield Model Railway Club's engineering section, together with a merry peacock accompanist, had just completed the permanent way for a new railway at the nearby Bentley Wildfowl Park and Motor Museum. However, one critical component remained before the first train could be run because, as I understood it, and no matter their size, all railways ultimately need a track on which to run their trains. Uckfield ‘84 September arrived and with it, the date of the club's annual exhibition, a three-day affair and the highlight of its fundraising calendar. Bluebell would be on show, together with her complete but unpainted Caledonian Railway sibling, their first public outing in both cases. This year, in addition to funding the usual club expenses,…

ROB ROY RALLY The sun always shines on the Rob Roy Rally. Sadly, last year it illuminated a scene reminiscent of a British Railways locomotive depot in the early 1960s, showing a depleted number of steam engines ‘on shed’. Just three Rob Roys posed on the service line in the morning of September 17th (photo 1). At least they weren't on the scrap line! Many factors may have contributed to the low numbers - the rocketing cost of living and fuel, the recent passing of Her Majesty the Queen and a nearby steam rally all may have been factors. Rob (of brother Roy) was suffering from Covid, as others may have done. Ian Horsfield, of the host club, was of course present with his, as yet, unpainted locomotive. Also from…

A good working steam locomotive needs to be set up balanced on its axles for best tractive effort, something that I have been working on for my model of 4472 in five-inch gauge. Before building the weighbridge, I studied how locomotives were weighed during the golden era of steam and also spoke to those who have first-hand experience on weighing 4472 (now 60103) in preservation. The full-size weighbridge design as fitted in Doncaster in 1935 was very clever and intricate - far too involved for our purpose but we can cheat with electronics. There are a couple of good images in the book LNER Workshops; Development, Expansion and Demise by Peter Tuffrey. The relevant information is in the ‘Doncaster’ chapter, pages 87-88, where there are two photographs worth study. One…

BRIDGET Continued from p.386, M.E.4712 March 10 The dome Of course, the dome is one of the most visually significant parts of most locomotives and this was no exception. The dome came as a gunmetal casting as shown in photo 23. However, I was to discover two quite serious defects in this casting: firstly, the core had not been placed centrally so that on one side the casting wall was 7 mm thick and the other only 3 mm thick; secondly, at some point someone had dropped the casting putting a small but not insignificant dent in the side. Of course, Sod's law applied and the dent was on the thin side of the casting. Given that I had bought the casting second hand and that the seller himself had…