Granville Tailer Woods was an inventor who held more than 60 patents in the U.S. He was the first African American mechanical and electrical engineer after the Civil War. Self-taught, he concentrated most of his work on trains and streetcars. One of his notable inventions was a device he called the Synchronous Multiplex Railway Telegraph, a variation of induction telegraph which relied on ambient static electricity from existing telegraph lines to send messages between train stations and moving trains. His work assured a safer and better public transportation system for the cities of the United States.