Standard time
In 1870 Charles F. Dowd proposed four time zones based on the meridian through Washington, DC for North American railroads. In 1872 he revised his proposal to base it on the Greenwich meridian. Sandford Fleming, a Scottish-born engineer operating in Canada, proposed worldwide Standard Time at a meeting of the Royal Canadian Institute on February 8, 1879. Cleveland Abbe advocated standard time to better coordinate international weather observations and resultant weather forecasts, which had been coordinated using local solar time. In 1879 he recommended four time zones across the contiguous United States, based upon Greenwich Mean Time. The General Time Convention (renamed the American Railway Association in 1891), an organization of US railroads charged with coordinating schedules and operating standards, became increasingly concerned that if the US government adopted a standard time scheme it would be disadvantageous to its member railroads. William F. Allen, the Convention secretary, argued that North American railroads should adopt a five-zone standard, similar to the one in use today, to avoid government action. On October 11, 1883, the heads of the major railroads met in Chicago at the Grand Pacific Hotel and agreed to adopt Allen's proposed system.
Effects of time zones on North American broadcasting
The most common set of programming chosen by stations aligned with the Big Three television networks (ABC, CBS and NBC) is to air a local newscast at 5:00 p.m., national news at 5:30 p.m., another local newscast at 6:00 p.m. and syndicated programming at 6:30 p.m., though some Fox stations that maintain a newscast schedule comparable to stations tied to the Big Three (commonly stations that were former ABC, NBC and CBS affiliates themselves) carry a 60- or 90-minute block of news from 5:00 to 6:00 (or 6:30) p.m. with an additional half-hour of local news in the 5:30 p.m. timeslot as Fox does not air a national evening newscast; a few stations not affiliated with the Big Four networks, such as WGN-TV, KTLA in Los Angeles and WJXT in Jacksonville, Florida, follow a similar scheduling format with their early evening newscasts. Most Big Three affiliates in the Eastern and Pacific time zones follow this early evening newscast model as well, running a 90-minute block of news from 5:00 to 6:30 p.m., particularly if they run a network's national evening newscast at 6:30 p.m. Eastern and Pacific Time. Some stations, regardless of time zone, even show a newscast from 6:00 to 7:00 p.m., which if run on a network station in the Central or Mountain time zones would lead into primetime network programming. Some television stations (such as WKYC and WJW in Cleveland, Ohio, or WJAR in Providence, Rhode Island) have recently begun using the fact that primetime in the Eastern Time Zone begins at 8:00 p.m. to their advantage by carrying a newscast during the 7:00 p.m. hour, generally in order to attract viewers who work longer days and cannot return home to watch a 5:00 or 6:00 p.m. newscast.