Planet type 2-2-0, 1830: Liverpool and Manchester Railway.

"One of the most marked characteristics in the working of the Rocket, observed very clearly during the Rainhill trials, and criticized by opponents of the Stephensons, was the swaying jerky action of the engine, attributable to the mounting of the cylinders high up on the side of the smokebox. Later engines of the 'Rocket' type had the cylinders mounted more nearly horizontal, but still outside the frames. The use of inside cylinders on the Planet in 1830 -- probably the very first case in the world -- was not wholly due to a desire to get smoother riding, but due to a suggestion made to Robert Stephenson by Richard Trevithick the great Cornish pioneer, who had found in repairing an old beam engine that he obtained an almost sensational economy of fuel by fitting a jacket round the cylinder to prevent loss of heat by radiation. On the Planet Stephenson enclosed the cylinders within the smokebox. The engine also incorporated the first use of 'sandwich' frames, which were formed of ash or oak, strengthened by iron plates inside and out. These gave flexibility and a great strength, and were a distinctive feature -- for example- of many broad gauge locomotives on the Great Western Railway in later years. The Planet was thus very much a landmark in locomotive history." [Nock, pp. 113-14]


Nock, O. S. The Pocket Encylopaedia of British Steam Locomotives. Illustrations by Clifford and Wendy Meadway. Poole: Blandford Press, 1964.

Last modified 10 September 2004