Trans-Siberian Railway essential for transporting strategic materials from the USSR to China and North Korea according to the Australia Station Intelligence Summary dated7 January 1955

An item reported that the Trans-Siberian Railway was of vital importance for supplying strategic materials by the USSR to China and North Korea. Altenatives were the long sea route via the Indian Ocean or the Northern Sea Route which was not only long but only 2-3 months during summer time open.

Source

Website Royal Australian Navy, Sea Power Centre.