サミュエル・ラングレー
Until 1883, each United States railroad chose its own time standards. The Pennsylvania Railroad used the "Allegheny Time" system, an astronomical timekeeping service which had been developed by Samuel Pierpont Langley at the University of Pittsburgh’s Allegheny Observatory (then known as the Western University of Pennsylvania, located in Pittsburgh, Pennsylvania). Instituted in 1869, the Allegheny Observatory's service is believed to have been the first regular and systematic system of time distribution to railroads and cities as well as the origin of the modern standard time system. By 1870 the Allegheny Time service extended over 2,500 miles with 300 telegraph offices receiving time signals.