In 1851 he moved to Switzerland to join the Sulzer company. In 1871 he left Sulzer to set up Swiss Locomotive and Machine Works (SLM). While at SLM he invented the Brown valve gear, a radial valve gear for steam engines. He became involved in the development of electric locomotives in the 1880s. In 1885 he became manager of Maschinenfabrik Oerlikon and in 1890 he set up Charles Brown and Company at 91 Rione Amedeo, Naples, Italy.
Charles Brown died on 6 October 1905 at Basel.