Which locomotive hauled the first public train on the Stockton and Darlington Railway in 1825?

Locomotion No. 1 hauled the first public train on the Stockton and Darlington Railway in 1825.

Built by George Stephenson and his son Robert at the Forth Street Works in Newcastle, the four-wheeled steam locomotive was originally called Active. It was renamed Locomotion before the railway opened. On 27 September 1825, it hauled a train carrying passengers, coal, and railway officials from Darlington to Stockton.

The Stockton and Darlington Railway was not exclusively a passenger railway: its main purpose was transporting coal from mines to the River Tees. The opening demonstrated that steam locomotives could work on a public railway, helping establish the model later used by major railway companies.

Locomotion No. 1 is sometimes confused with Rocket, which won the Rainhill Trials in 1829 and later worked on the Liverpool and Manchester Railway. Locomotion No. 1 is preserved at the Head of Steam museum in Darlington.