The Maine Central Railroad Company main line extended from Portland, Maine, east to the Canada–US border with New Brunswick at the Saint Croix–Vanceboro Railway Bridge. It is the transportation artery linking Maine cities to the national railway network. Sections of the main line had been built by predecessor railroads consolidated as the Maine Central in 1862 and extended to the Canada–US border in 1882. Through the early 20th century, the main line was double track from South Portland to Royal Junction, where it split into a lower road through Brunswick and Augusta and a back road through Lewiston which converged at Waterville into single track to Bangor and points east.[1] Westbound trains typically used the lower road with lighter grades, while eastbound trains of empty cars used the back road.[2] This historical description does not include changes following purchase of the Maine Central Railroad by Guilford Transportation Industries in 1981 and subsequent operation as part of Pan Am Railways.