New York Subway Extension Begins Service

August 5, 1904 saw the opening of a key segment of New York City's first subway line operated by the Interborough Rapid Transit Company. This extension from 145th Street to 157th Street utilized innovative deep-bore tunneling techniques beneath the Harlem River. Electric multiple-unit trains powered by third-rail systems replaced earlier steam efforts. Key figures included Chief Engineer William Barclay Parsons and financier August Belmont. The project overcame challenging geology and urban density, setting standards for American subway engineering. It dramatically improved commuter access, supporting population growth and economic integration across boroughs, with lasting effects on urban planning worldwide.