 With the introduction of the electrical telegraph in 1855 between Kristiania (Oslo) and Drammen, the local time of Copenhagen, Denmark was used for this purpose, until 1866 when it was replaced by Oslo local time.The railways from the Eastern terminus (Østbanen) in Oslo used Oslo local time, while the railways from the Western terminus (Vestbanen) used Drammen local time, a difference of 4 minutes.The unconnected railways from Bergen and Stavanger used these cities local time, both 22 minutes after Oslo time.