What was the name of the locomotive used at the opening of the Stockton and Darlington Railway?

The locomotive used at the opening of the Stockton and Darlington Railway was Locomotion No. 1.

Built in 1825 by Robert Stephenson and Company, the engine was originally named Active. It was later renamed Locomotion and became known as Locomotion No. 1 after the railway’s locomotives were numbered. George Stephenson drove it during the railway’s opening on 27 September 1825.

The inaugural train was an extraordinary combination of coal wagons, passenger vehicles, guests, and workers. Locomotion hauled eleven wagons of coal, the passenger coach Experiment, and roughly 20 additional wagons. The train covered the first section of the journey slowly, but it reached approximately 15 miles per hour on one stretch—remarkable performance for the period.

It is easy to confuse this engine with Rocket, which won the Rainhill Trials in 1829 and became associated with the Liverpool and Manchester Railway. Sans Pareil was another Rainhill competitor, while Puffing Billy was an earlier colliery locomotive. Locomotion No. 1 continued working until 1850, survived conversion into a stationary engine, and was preserved in 1857.