Electric Railway Company of the United States

This company was incorporated on May 5, 1883, to develop improvements in electrical propulsion and to manufacture and sell electrical apparatus for railways. It controlled all of Edison's railway patents. The company assigned Edison's patents to Edison General Electric in 1889 and was liquidated in 1897.

Pohatcong Railroad Company

This company was incorporated in New Jersey on October 21, 1907, and leased to the Edison Portland Cement Company. Edison was the owner of all the issued stock until his death on October 18, 1931. The company was dissolved on December 8, 1964.

Port Huron and Gratiot Street Railway Company

This company was founded in 1866 by Edison's brother Pitt and others to connect the Grand Trunk Railway depot in Fort Gratiot to the town of Port Huron, Michigan. Thomas Edison became an investor in the railway in November 1871.

Port Huron Railway Company

This company was formed in 1877 as a merger of the Port Huron and Gratiot Street Railway and the City Railroad Company, which had been formed in 1873 by some of the original investors in the Port Huron Company after they had a falling out with Pitt Edison. Thomas Edison took 158 shares in the new company.