Richard Trevithick (Illogan, Cornwall, 1771 – Dartford, 1833), a Cornish mining engineer, builds on 21 February 1804 the first steam locomotive in history at the Penydarren ironworks (Merthyr Tydfil, Wales): it hauls ten tons of iron and seventy men over 16 km at about 8 km/h on cast-iron rails. The key to Trevithick's contribution is high-pressure steam: while Watt insisted on low pressures for safety and patent reasons, Trevithick uses steam at more than 3 atmospheres, making possible an engine compact and powerful enough to move on rails. The rails broke under the weight, and the project was not commercialized; Trevithick died in poverty. Stephenson takes up his principle 25 years later.