Built as a prototype to win a speed trial, the engine was soon superseded by improved designs, such as Stephenson's Northumbrian and Planet designs, both of 1830.

Within a few years, the Rocket itself had been much modified to be similar to the Northumbrian class.
The cylinders were altered to a near-horizontal position, compared to the angled arrangement as new; the firebox capacity was enlarged and the shape simplified; and the locomotive was given a drum smokebox.
These arrangements can be seen in the engine today.

Such are the changes in the engine from 1829 that The Engineer magazine, circa 1884, concluded that "it seems to us indisputable that the Rocket of 1829 and 1830 were totally different engines".
Built as a prototype to win a speed trial, the engine was soon superseded by improved designs, such as Stephenson's Northumbrian and Planet designs, both of 1830.
Within a few years, the Rocket itself had been much modified to be similar to the Northumbrian class. The cylinders were altered to a near-horizontal position, compared to the angled arrangement as new; the firebox capacity was enlarged and the shape simplified; and the locomotive was given a drum smokebox. These arrangements can be seen in the engine today.
Such are the changes in the engine from 1829 that The Engineer magazine, circa 1884, concluded that "it seems to us indisputable that the Rocket of 1829 and 1830 were totally different engines".
Stephenson's Rocket