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.
UTC−06:00
UTC−06:00 is a time offset that subtracts six hours from Coordinated Universal Time (UTC). 
In North America, it is observed in the Central Time Zone during standard time, and in the Mountain Time Zone during the other eight months (see Daylight saving time). Several Latin American countries and a few other places use it year round.