What did George wetinghouse jr invent?

George Westinghouse, Jr was an American entrepenur and engineer who invented the railroad air brake and was a pioneer of the electrical industry. Westinghouse was one of Thomas Edison's main rivals in the early implementation of the American electricity system. Westinghouse's system using alternating current ultimately prevailed over Edison's insistence on direct current. In 1911, he received the AIEE Adisson's Medal 'For meritorious achievement in connection with the development of the alternating current system light'.