Sketch of a spring-loaded safety valve from Hackworth's note-book, 1827-28 (pencil on paper)

Pencil sketch of a spring-loaded safety valve, adjacent to an entry dated June 27 1828. Originally a blacksmith, Hackworth (1786-1850) was a pioneer in the construction of steam locomotives. In 1808 he worked at Wylam Colliery where he helped William Hedley (1779-1843) produce the 'Puffing Billy' locomotive. In 1825 he was appointed to the Stockton and Darlington Railway by George Stephenson (1781-1848), and in doing so became the first ever locomotive superintendent. There, he built the famous 'Royal George' and 'Sans Pareil' which was entered in the Rainhill Trials of 1829 and was subsequently used on the Bolton and Leigh Railway. In 1833 Hackworth left the Stockton and Darlington Railway to form his own successful Soho locomotive building company.