Undated drawing, outside elevation of long-boiler, new type, with outside cylinders, stroke increased to 24"; the wheel spokes are of bent angle iron, introduced by Robert Stephenson about this time in place of the tubular spoke. A locomotive of this type, described in the makers' books as "Pattern engine" was supplied to the Marseilles Avignon Railway, a model of the type is to be seen at the Conservatoire des Arts et Metiers, Paris. Note the expansion link of box form. Description from A Century of Locomotive Building by Robert Stephenson & Co 1823-1923, J G H Warren, p 354. Drawing reference - 98.