George and Robert Stephenson's Rocket is arguably the most enduring silhouette in railway history. But why was Rocket that special? And why does the surviving locomotive look so unlike the striking yellow image that we are familiar with from books, postage stamps and the five pound note? Rocket was built to take part in The Rainhill Trials, the competition to find a locomotive design to pull trains on the world's first passenger line, the Liverpool and Manchester. The trials caught the public's imagination and its victor, Rocket, became a sensation. It quickly became of symbol of technological progress. The Stephensons' engine set the pattern for future world steam locomotive development for the next 130 years. But would the steam locomotive have developed differently if Rocket had not won the trials? All these questions while exploring in words and pictures the machine that became the metaphor for what is seen as Britain's greatest gift to the industrial world: the steam locomotive.