The situation's precariousness was demonstrated by an outbreak of pneumonic plague in Hailar, a town at the western end of the Chinese Eastern Railway, in October 1920. Chinese troops were present in great number and turned railway quarantine into a farce. The soldiers freed some of their comrades who had been imprisoned as contacts, and they escaped to the mining town of Dalainor on the Amur River, where a quarter of the population died. In the other direction, all of the towns along the Chinese Eastern Railway as far as Vladivostok were infected. Around 9,000 died, while only a few contacts were able to reach south Manchuria.