"Thank you. This is a rather nice commemorative plaque featuring a Great Western 'Castle' class locomotive. Modelling can be very variable on this sort of objet but this is quite well done. There's a limit, of course, to how much detail can be incorporated but the classic lines of the 'Castle' are quite clear."
"Churchward introduced the Great Western 'Star' class which laid out the basic format for a four cylinder express locomotive. Divided drive, with two inside cylinders set well forward connected to the leading cranked driving axle and two outside cylinders driving the next axle via crankpins. Although Stephenson link motion had been used with complete success on other types, Churchward decided to fit two sets of Walschaert's motion inside the frames working the piston valves on the inside cylinders directly and the piston valves for the outside cylinders via rocking levers. Initially, the 'Atlantic' wheel arrangement (4-4-2) was to be used, as on the De Glehn compounds he'd evaluated, but Churchward became convinced that the extra adhesion contributed by a pair of coupled wheels, rather than a pony truck, would be more valuable, giving rise to the classic Great Western 4-6-0. The 'Castle' closely followed the outline of the earlier 'Star' but Collett did provide a somewhat improved cab, allowing us to quickly identify this plaque as a 'Castle'."
"Turning to the material which has been used for this plaque, the brown colouration suggests terracotta which, in the right hands, can provide the level of detail we see here... I beg your pardon? Chocolate? Did you say CHOCOLATE? You are surely mistaken" ...
(MUNCH) ... "Certainly, it's rather softer than I would have expected. Terracotta requires the correct kiln temperature for 'firing' to produce a durable artefact ..."
(MUNCH) ... "Of course, Churchward used only a low degree of superheat and it wasn't until after the Second World War that higher superheat was used. The traditional Great Western sight feed lubricator was not sufficiently reliable with the resulting higher steam temperatures and so a mechanical lubricator was used for the cylinder oil. A double chimney and blastpipe was introduced, to reduce back pressure and consequent power losses" ...
(MUNCH) ... "The name of Sam Ell is associated with this post-war work at Swindon where the steaming of a number of classes was significantly improved, often by quite minor changes to the draughting. By this time, the work of Lemaitre, Chapelon and Kylala was becoming well known" ...
(MUNCH) ... "Now, looking again at this commemorative plaque ... Oh dear, it seems to have gone. Next object, please!"
