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.