Model steam locomotive, scale 1:8, Stephenson's locomotive "Planet", 1830, made by the Science Museum in 1967.

The design of the "Planet" of 1830 was a great advance on that of the "Rocket" of 1829 and formed the basis on which much of the later development of the steam locomotive was founded. The main improvements were that the fire-tube boiler was fitted with an enclosed firebox and with a smokebox having a central exhaust nozzle, and that the engine was arranged horizontally with the cylinders under the smokebox between the frames.

The locomotive, which was of the 2-2-0 type, was delivered to the Liverpool & Manchester Railway Company on November 29th, 1830, and on December 4th drew 18 wagons with a gross weight of about 80 tons. The journey of 25 miles between Liverpool and Manchester, with three stops and additional engine assistance on inclines, took 174 minutes. Its success caused the Directors to adopt it as the standard design on the railway for a time. On February 15th, 1833, the "Planet" had run 41,000 miles, and was reported as being in good condition.

This model is 1:8 scale and was made by the Science Museum in 1967.