 The facilities, unlike those at Port Arthur, featured many casemated underground structures, the thickness of the concrete provided protection against fire from guns.The garrison of the fortress was to consist of 48 infantry battalions, 15 fortress-artillery battalions, eight batteries of field and mountain artillery manned by two battalions, a battalion of miners, a telegraph battalion, a supply battalion, two aeronautics companies, and three Cossack squadrons.The units stationed at the fortress consisted of