US inventor, one of the first and foremost of black American scientists. He invented a ‘troller’, or grooved metal wheel, that allowed street cars (soon known as ‘trolleys’) to collect electric power from overhead wires. His most important invention (made in 1887) was the multiplex telegraph (also known as the induction telegraph, or block system). He defeated Thomas Edison's legal suit that challenged his patent, then turned down Edison's offer to make him a partner.
Born in Ohio to free black American parents, he received sketchy schooling, leaving in his early teens to start a variety of jobs – in a railroad machine shop, as a railroad engineer, in a steel mill, as an engineer on a British ship, and then back on the railroad. At some point, however – evidently in New York, New York, between 1876 and 1878 – he took some courses in electricity, which he evidently realized held the key to the future, and in 1881 he settled in Cincinnati, Ohio, where he eventually was able to set up his own company to develop, manufacture, and sell electrical apparatus.
His first invention was for an improved steam boiler furnace, but thereafter his patents were mainly for electrical devices, such as his second invention, an improved telephone transmitter. The patent for his device combining the telephone and telegraph was bought by Alexander Graham Bell and the payment freed Woods to devote himself to his own researches.
After receiving a patent for his multiplex telegraph, he reorganized his Cincinnati company as the Woods Electric Co., but in 1890 he moved his own research operations to New York, where he was joined by a brother, Lyates Woods, who also had several inventions of his own. Granville's next important invention (made in 1901) was the power pick-up device that is the basis of the so-called ‘third rail’ used by electric-powered transit systems. He received patents for an improved air-brake system 1902–05. By the time of his death he had some 60 patents.