This Photograph shows a 3D printed working model of LNWR Locomotive No. 153, originally built by Robert Stephenson & Co. in 1846. No.153 was a 'Long Boiler' express locomotive, developed from the 'Great A', the famous 'Gauge War' engine. The 'Great A' took part in the gauge trials of 1845/6 and demonstrated that it could return similar performance and efficiency to the broad gauge 'Firefly' with which it competed. It was the 'Great A' that finally sealed the fate of the broad gauge, and ensured that Stephenson's'narrow gauge' became the standard of railways all around the world. No drawings of the 'Great A' survive, saving a single elevation made by David Joy from the engine itself. Joy, creator of the 'Jenny Lind', said that this "was the first engine on which he ever rode". Fortunately, Joy also made an accurate tracing of Stephenson's drawing for the succeeding and very successful 'A type', of which this engine is an example. Only one photograph of a license built 'A Type' is known to exist, and so this model is intended to portray a scene otherwiselost to human eyes.

The model represents a compilation of details from contemporary sources and is thought to present a reasonably accurate view of No.153. It is built to a scale of 10mm / ft and 45mm (Gauge 1 or G scale) track gauge. The version shown here contains certain innacuracies (running boards too narrow, boiler not oval) which are corrected in subsequent prints. Unfortunately the oval boiler (A big challenge for CAD software!) is scarcely detectable in the finished model.

The 3D worksheet (Photo) contains scans of original tracings, engravings and woodcuts adjusted to scale. 2D working drawings are traced from these originals and then extruded or spun to form 3D components whch are assembled into the completed model. The model is printed SLS (Selective Laser Sintering) Nylon by Shapeways, Inc., and is made in one piece except for moving parts and certain fittings. It is tender powered by a 3.7v cell phone battery and coreless motor driving through helical reduction gears and chain transmission. Locomotive and tender run on ball races and can operate a train of 13 contemporary coaches at a scale 40 mph for an hour or more. (Note: the tender shown here is actually a Sharp Stewart design: the correct Stephenson tender is in preparation. Tenders are more difficult subject than locomotives because few drawings exist. This one is from DK Clark in 'Railway Machinery' and is actually for long boiler 0-6-0 'Sphynx', another forthcoming model.) Photos: Author