Walter was one of the founders of the Southampton and London Railway and Dock Company, in 1831, with
Abel Rous Dottin, and
Robert Johnston (1783–1839) from Jamaica. The company failed.
George Thomas Landmann in October 1831 brought Walter into planning for the
London and Greenwich Railway, and an initial meeting was held in Dottin's house in Argyle Street, London. The company's base was Walter's insurance office. In July 1837, Dottin and Walter resigned as directors. In 1835 Walter founded and subsidised the
Railway Magazine, having seen the potential in the ''
Mechanics' Magazine'' and its railway promotion; he brought in
John Yonge Akerman as its editor. It was the first specialist railway periodical, and Walter used it to publicise the London & Greenwich, where Akerman was his replacement as secretary, and his other interests. In 1836 he sold it to
John Herapath. ==Later life==