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.
Chamorro Time Zone
Chamorro Standard Time shares the same time as Australian Eastern Standard Time.The Mariana Islands were not part of any time zone legislated by the U.S. Congress until the Chamorro time zone was established by Public Law 106-564 on December 23, 2000. Prior to 2000, Guam's standard time was based on territorial Public Law 5-25 (1959) which designated the time Guam Standard Time. The law (Guam Code Annotated, Title 1, Section 1010) was established long before the Northern Mariana Islands came under U.S. sovereignty in 1986, and still remains in the book today despite federal overlap.