Regulations of the watches used by critical personnel on the railroads (engineer, conductor, switch yard controllers, etc.)
In the United States, the American Railway Association held a meeting in 1887, which resulted a fairly standardized set of requirements,[2] but not all railroads adopted them.
Ball's career eventually led to his being the time inspector on more than half the United States' railways, leading to a far more uniform set of standards in the U.S. A typical railroad's requirements for a watch in the early 20th century might include: The minimum requirements were raised several times as watch-making technology progressed, and the watch companies produced newer, even more reliable models.
By World War II, many railroads required watches that were of a much higher grade than those made to comply with the original 1891 standard.
The Time Signal Service of the United States Naval Observatory was used to ensure accuracy of railroad chronometers and schedule American rail transport.