International Meridian Conference
On 11 October 1883, a convention of railroad executives met in Chicago and agreed to the implementation of five time zones in North America, using as a basis Greenwich Mean Time. Before the invitations to the Washington conference were sent out on December 1, the joint efforts of Abbe, Fleming and William Frederick Allen, Secretary of the US railways' "General Time Convention" and Managing Editor of the "Travellers' Official Guide to the Railways", had brought the US railway companies to an agreement which led to standard railway time being introduced at noon on 18 November 1883 across the nation. Although this was not legally established until 1918, there was thus a strong sense of "fait accompli" that preceded the Washington conference, although setting local times was not part of the remit of the conference.
Atlantic Time Zone
No portion of the continental United States currently uses Atlantic Time, although it is used by the territories of Puerto Rico and the U.S. Virgin Islands. A number of New England states are considering a regional change to Atlantic Standard Time year-round (with no observance of daylight saving time), even though only a small portion of Maine lies to the east of the 67.5°W theoretical extent of this zone. Florida is in the process of enacting a similar change; in both cases any changes will need to be approved by the United States Department of Transportation and the United States Congress.A Massachusetts commission concluded in 2017 that the benefits of changing to Atlantic Standard Time year-round would outweigh the disadvantages, provided that a majority of northeastern states made the same change. In May 2017, the Maine Senate approved a change to AST, on the condition that there would be a referendum, and that Massachusetts and New Hampshire decided to make the same switch. Also in 2017, the New Hampshire House of Representatives approved a bill in favour of a regional change, but this was voted down by the state's Senate. Similar bills have been put forward in Connecticut and Rhode Island.