Prior to 1883, the time of day was a local matter set by individual cities and varied from town to town. Railroads chose their own standard times, many syncing their operations with New York City Standard Time or Chicago Standard Time. Due to years of problems associated with time variances of 30 minutes or greater, at noon on November 18, 1883, the major railroads in the US and Canada implemented Standard Time and established the time zones we use today.