The first steam locomotive to run on rails did so in 1804. Richard Trevithick’s high-pressure steam locomotive hauled a train along the Merthyr Tramroad in South Wales on 21 February that year.
The locomotive began at the Penydarren Ironworks near Merthyr Tydfil and travelled toward the canal at Abercynon. On its first authenticated journey, it hauled roughly 10 tons of iron and several carriages carrying passengers. Trevithick’s use of high-pressure steam made the engine compact and powerful enough for rail transport.
The achievement was experimental rather than the beginning of a reliable railway service. The heavy locomotive damaged the cast-iron plateway, and the system was not commercially successful. Even so, it proved that steam power could move loads on rails.
This date is often confused with 1825, when George Stephenson’s Locomotion No. 1 helped open the Stockton and Darlington Railway, the first public railway to use steam locomotives. Stephenson’s Rocket came later, in 1829.