Passing Time

This is probably the most well known clock in the US - the ball clock above the information booth at Grand Central Station. Many have used it not only to tell time - its most important function - but it has also served as a meeting place for travelers for nearly a century. The four faces of the brass ball clock are solid opal - Sotheby's and Christie's have valued it at between $10-$20 million. It was built in 1913 by the Self Winding Clock Company, a firm started by Charles Pratt (oil tycoon and founder of Pratt Institute) and engineer Henry Chester Pond in a Pratt owned building at 205 Willoughby Street in Brooklyn, New York (later moved to Varick Street in Manhattan). From 1886 to 1957, the company built 50,000 clocks. These clocks were self powered by dry cell batteries and automatic spring winding and synchronization. When properly maintained, they were highly accurate. Their clocks were used everywhere around the world: the Metropolitan Tower clock, the House of Representatives, battleships, NYC and London subways, railroads, airlines, the Strategic Air Command, stock exchanges, hospitals, schools, hotels, universities, department stores and broadcasting systems. Over time, however, maintaining accuracy of all these historic clocks was a problem, so recently, all of the more than 55 clocks have been synchronized to a continuous satellite signal sent from an atomic clock at the U.S. Naval Observatory - the clocks are now accurate to within two microseconds. Everything is controlled by the terminal's master clock, located behind locked doors near Track 117 on the lower level ...