Tony Rest’s
STEPHENSON’S ROCKET
This model of Stephenson’s Rocket was shown at Guildford by Tony Rest. As every schoolboy knows, Stephenson’s Rocket was the first ‘modern‘ locomotive which succeeded at the famous Rainhill Trials. Rocket was not the first steam locomotive, it was, however, the first to bring together several innovations to produce the most advanced locomotive of its day. It became the template for most steam engines in the following 150 years. The locomotive is preserved on display in the Science Museum in London.

The locomotive had a tall smokestack chimney at the front, a cylindrical boiler in the middle, and a separate firebox at the rear. The large front pair of wooden wheels were driven by two external cylinders set at an angle. The smaller rear wheels were not coupled to the driving wheels, giving the 0-2-2 wheel arrangement. Rocket used a multi-tubular boiler design, previous locomotive boilers consisted of a single pipe surrounded by water. Rocket also used a blast pipe, feeding the exhaust steam from the cylinders into the base of the chimney to induce a partial vacuum and pull air through the fire.

Rocket had two cylinders set at angle from the horizontal, with the pistons driving a pair of 4’  8.5” dia wheels. Previous designs had the cylinders positioned vertically, which gave the engines an uneven swaying motion as they ran along the track. Subsequently, Rocket was modified so that the cylinders were set closer to horizontal, a layout which influenced most designs that followed.

The firebox was separate from the boiler and was double walled, with a water jacket between. Stephenson recognized that the hottest part of the boiler, and so the most effective for evaporating water, was that surrounding the fire itself. This firebox was heated by radiant heat from glowing coke, not just convection from the hot exhaust gas. Locomotives of Rocket's era were fired by coke rather than coal.