16mm Couplings

Firstly, we are very sorry to have missed the 16mm AGM at Peterborough. We were looking forward to seeing old friends and customers, catching up with the news and gaining valuable feedback. It was a loss. When we made our booking, we were confident. We were both double-vaccinated, as, no doubt, many other attendees would be. The chance of catching COVID was much reduced, we thought, as was the prospect of passing it on to others. As we came nearer to Saturday 26th, there were alarming rumours that the coronavirus was mutating. No-one was sure whether these new forms might, or might not, affect people even though they had been vaccinated. In the end, no-one could prove a negative without time to gather evidence. We felt it safest to stay away. As you all know, we feel that our 16mm group are friends, and wouldn’t it be terrible to pass on something to our friendship circle? We cancelled. Thank you everyone who has got in touch. Yes, we are fine. We weren’t kept away by illness.

Instead of going to the Show, Malcolm has been at his workbench, putting together the 16mm scale Baldwin Gas Mechanical locotractors. We are pleased to send you photographs of progress. We have also been involved in ‘live running’ with friends. There is nothing quite like putting a model, however beautiful, through its paces on scale railway track. Although rolling stock looks perfect on the bench, once they start moving, problems become apparent. When making up a train of wagons which had been designed by another hand, we became conscious of the modellers’ dilemma. We all want our models to run as well as possible as long as they are as accurate as possible. The design and making of models is the art of satisfying these competing demands. Like any art, it can lead to slightly surprising results. On this particular running day, the problems were with the couplings. There are several proprietary model couplings which serve the modeller reliably, attaching and detaching as required. The only trouble is that they are underscale, overscale or generally non-prototypical. The wagon in question (not Wrightscale, but a beloved item in Malcolm’s treasure chest) had beautiful ‘deadscale’ couplings. They looked the part but kept on detaching mid-run. Malcolm is still wondering how to fix the problem without losing the look.

While moving along this track, so to speak, here are some thoughts about couplings as used on the Péchot system. As our friends know, this 60cm gauge system was devised by Prosper Péchot in the 1880s for the service of the French artillery. He used the designs of Paul Decauville, famous for his prefabricated agricultural railways, and improved them. His system was portable and relatively lightweight, just like the Decauville, yet it could carry significant loads, such as were needed by an army in the 1880s. Among the improvements designed by Péchot was the coupling. The drawing shown here is reproduced courtesy of the CAA, France. It was drawn in the 1890s as coupling to the twelve tonne six-wheeled bogie, but the general proinciples apply. Each bogie had a fully sprung buffer-coupling at one end and a tampon sec at the other. The literal meaning of sec is dry; in this context it meant with very much simpler springing. The link was completed with chains, to be fixed to the next item of rolling stock. Part of the genius of the design was that the link was between bogies, rather than the wagon superstructure. The bogie springing compensated for roll, dip, sheer and shock and generally kept the train moving, even on poor track.

Though many authorities dislike admitting it, the German army copied the Péchot design. They then improved it. Their bogie-mounted coupling was a ‘sprung balance’, lessening the need for elaborate springing in the body of the bogie. Because one small part had to do so much, the German wagons were relatively short-lived. In contrast, many Péchot bogies survive to this day. The Péchot story is fascinating, full of human interest. 25 years later, his system and material inspired by it were used by both the Allies and the Central Powers during the First World War. Descendents of the Péchot coupling features on French, British and AEF rolling stock. The Baldwin Gas Mechanical was devised in the USA for use in Europe by both the American Expeditionary Force and the French Army. It was supplied with couplings reminiscent of the Péchot original, as photographs in the maker’s ‘Instructions for operation’ attest. Rolling stock also benefited from the Péchot design. As well as the Pershing bogie, the AEF commissioned and used rolling stock which had ‘family resemblances’ to the Péchot design. Rich Dunn has a useful page showing both styles. Though ubiquitous, the Pershing style did not have the sturdiness and manoeuvrability which characterises ‘son of’ Péchot, as can be inferred from Dunn’s text.

Back to our models; this view of the end of a Wrightscale WD Class D bogie open wagon shows a compromise between deadscale faithfulness to the Péchot-inspired original and the rough-and-tumble of a 16mm group fun-run. Illustrations 53, 54 and 55 in Light Railways of The First World War show prototypes. The sharp-eyed reader will point out that the coupling on the WD model has an addition, a tried and trusted proprietary link pin. Easily joined and released, it makes running a live steam model rather easier. As mentioned above, modelling is the art of reconciling irreconcilable aims, deadscale accuracy and function. If you think about it, life is like a model railway. It is partly rules and partly trying to escape them. WJK Davies Light Railways of the First World War David and Charles 1967 The book is unfortunately out of print, but in the archives of the Imperial War museum, useful three quarter shots can now be seen online. Rich Dunn Narrow Gauge To No Man’s Land Benchmark 1990 especially page 113 Sarah Wright Colonel Péchot Tracks To The Trenches Birse Press 2014

Wrightscale 16mm Baldwin Gas Mechanical in progress. No coupler has yet been fitted!