Thomas Brassey, English engineer and businessman (d. 1870)
Thomas Brassey (7 November 1805 – 8 December 1870) was an English civil engineering contractor and manufacturer of building materials who was responsible for building much of the world's railways in the 19th century. By 1847, he had built about one-third of the railways in Britain, and by time of his death in 1870 he had built one in every twenty miles of railway in the world. This included three-quarters of the lines in France, major lines in many other European countries and in Canada, Australia, South America and India. He also built the structures associated with those railways, including docks, bridges, viaducts, stations, tunnels and drainage works.

As well as railway engineering, Brassey was active in the development of steamships, mines, locomotive factories, marine telegraphy, and water supply and sewage systems. He built part of the London sewerage system, still in operation today, and was a major shareholder in Brunel's The Great Eastern, the only ship large enough at the time to lay the first transatlantic telegraph cable across the North Atlantic, in 1864. He left a fortune of over £5 million, equivalent to about £600 million in 2020.