Kirov Railway

The line is of vital military importance because Murmansk is an ice-free port accessible via the Barents Sea: The [...] limiting factor in Russian overseas supply [in World War I] was not ocean shipping.

The primary Russian port, Arkhangel'sk, was served by a single narrow gauge line, which resulted in tremendous backlogs of stores.

[...] The Allies desperately wanted to avoid the White Sea closure by using the warm water ports of the western Murman Coast or Norway.

[...] More promising was the effort to build a seven hundred-mile railway from the ice-free Kola Inlet to the northern terminus of the Russian rail system.

[1] The northern part of the line, between Petrozavodsk and Kola, was built in 1915–1917: due to a lack of workers the Tsarist authorities deployed more than 40,000 German and Austrian prisoners of war to the construction.