Industrialists such as Andrew Carnegie, Henry Clay Frick, Andrew W. Mellon, and Charles M. Schwab built their fortunes in Pittsburgh. Also based in Pittsburgh was George Westinghouse, credited with such advancements as the air brake and founder of over 60 companies, including Westinghouse Air and Brake Company (1869), Union Switch & Signal (1881), and Westinghouse Electric Company (1886). Banks played a key role in Pittsburgh's development as these industrialists sought massive loans to upgrade plants, integrate industries and fund technological advances. For example, T. Mellon & Sons Bank, founded in 1869, helped to finance an aluminum reduction company that became Alcoa.