Firstly, the rocket used a multi-tubular boiler. In other words, hot gases from the firebox flowed across dozens of narrow tubes, each one filled with water. This made heat transfer from the fire to the water in the boiler far more effective. Until rocket, most locomotive boilers were little more than a cylinder of water built around a pipe running from the firebox to the chimney. Rocket's boiler, however, greatly increased the surface area for heat transfer, allowing steam to be produced at a much faster rate.

George Stephenson also included a 'blastpipe' for the first time in a locomotive. This used exhaust steam to help pull air through the firebox so the fire generated far more heat. To stop the firebox melting, the Stephensons even cooled the firebox with a trickle of cold water.

Designed and built to compete in the Rainhill Trails, a competition to select the locomotive for the Liverpool and Manchester Railway, Stephenson's masterpiece lived up to its name. It completed the 50-mile course without breaking down or using too much fuel, at an average speed of 12 miles per hour - no mean feat 175 years ago. The locomotive continued to work hard for the next 30 years until it finally retired. You can still see this steam revolutionary at The Science Museum in London.