Not so long ago, TOPWAR published a number of articles about the Battle of Verdun, and before that there were also materials about the fortress war of the First World War and the guns used against the then forts. And here the question arises: how was the experience of the First World War analyzed in relation to the fight against fortresses in the interwar period? What formed the basis of the various "lines" and "theories", what is the best way to overcome them? That is, what was written about this in the 20s, and what information was communicated to the same general public? Let's look at the magazine "Science and Technology" No. 34 for 1929, there was published an article "Modern Fortresses", which dealt with the vision of serf war that existed at that time and which formed the basis for the creation of many fortified zones on the borders of European countries on the eve of World War II.
“The appearance of rifled artillery in the second half of the 19th century had a strong impact on the plan and construction of fortifications. By this time, the external forms of the fortress received their final development, expressed in the fact that the stone in the parapet gave way to earth, and the fortress fence, so to speak, moved away from the fortress core it protected - a city, a railway junction or an important crossing, and broke up into a number of separate points called "forts". The forts surrounded the fortress core with a ring, the radius of which reached 6-8 km. The removal of the forts from the city was necessary to prevent the destruction of the fortifications from enemy artillery fire. To better cover the gaps between the forts, a second belt of forts was sometimes put forward. The gaps between the forts of the first and second lines were left at 4-6 km, subject to the presence of cross artillery fire between the forts. It was performed by intermediate caponiers or half-caponiers proposed by the Russian military specialist, Ing. K. I. Velichko. These gunners were in the forts.
Rifled artillery is distinguished by its range, firing accuracy and strong projectile action. Therefore, forts, which took the main blow of the enemy, and especially strong structures made of stone with very thick walls and vaults, strewn with large layers of earth, became the main means of defense. For greater strength, iron beams were used, and concrete began to appear. Old stone walls are also reinforced with concrete.
The further evolution of fortress buildings is caused by the appearance of high-explosive bombs, i.e. shells charged with a strong explosive (pyroxylin, melinite, TNT). Possessing tremendous destructive power, they do not explode immediately when the projectile hits the target, but after the projectile has used all its penetrating power (impact action). As a result of this property, the projectile penetrates the earthen covering of the fort and then explodes like a mine on the vault or close to the wall of the room, causing destruction by its high-explosive action.
Now the stone, as a building material, is falling away and is being replaced exclusively by the most durable materials: concrete, reinforced concrete and steel armor. The vaults and walls reach a thickness of 2-2.5 m, with additional sprinkling with a layer of earth of about 1 m. All buildings are trying to deepen as much as possible into the ground. The belt of forts is made double and moved forward 8-10 km. Forts turn into fort groups. Along with the forts, a separate defense of the gaps between the forts by field defensive structures ("redoubts") is organized. The system of mutual flanking fire of caponiers and half-caponiers is especially developing. The fortresses are supplied with huge reserves and numerous artillery. For safe communication in the forts, concrete underground passages - "posterns" are arranged. Extensive mechanization is being carried out: the guns stand under armored domes moving by electricity, the supply of heavy projectiles and charging are also electrified, narrow-gauge railways are drawn from the fortress core to the forts, strong searchlights are installed, the core of the fortress is equipped with workshops where electric power is also applied, etc. … etc.
The garrison of such a fortress has tens of thousands of fighters in its ranks and is supplied to a large extent with special military-technical units: engineering, automobile, aviation, railway, armored, communications, etc. All command is concentrated in the hands of one person - the commandant of the fortress.
Such fortresses close off important lines of operations and usually connect at the same time the cover of railway bridges across wide water lines. Hence their name - "tete-de-pont" (French word, literally - "head of the bridge"). If the bridges are protected by a fortress on both banks, as is usually the case, then this is a "double tete-de-pon". A single tete-de-pon covers the bridge from one (located in the side of the enemy) bank.
In those cases when it is necessary to block the passage through some narrowness ("defile"), for example, a pass in the mountains or a railway in a swampy lake area, then arrange a small fortress of 2-3, and sometimes one fort. But these forts receive very solid concrete, concrete-iron and armored covers, strong artillery and a sufficient garrison. Such a fort or a combination of forts is called "outpost fort". This is the same fortress, but more modest in size, since in the direction it covers, one cannot expect the appearance of large enemy forces with a powerful siege of artillery.
On the contrary, if it is necessary to protect a large area of strategic importance with a width of 50-60 and a depth of up to 100 km with the help of long-term fortifications, this task is carried out by combining a fortress (or fortresses) with outpost fortifications by field fortifications. It turns out a long-term fortified area. It is supplied with a garrison of such a size that would not only allow to defend the fortress positions, but would also enable the district commandant to withdraw part of the troops into the field and, relying on the forces and means of the district, to attack the enemy. Therefore, the size and organization of the garrison of the fortified area is close to an independent army.
Such fortified areas were before the World War in our country (the triangle of fortresses Warsaw - Zgerzh - Novogeorgievsk), among the Germans on the Russian border - Thorn - Kulm - Graudenz and on the French border - Metz - Thionville, and among the French - Verdun and the fortifications of the Meuse Heights. Now only the French are creating vast fortified areas on their own and Belgian territory against the Germans.
The parapet of the forts is proposed to be made of a concrete massif. Heavy cannons are installed on the valganga of the fort, the fort receives a system of underground (counter-mine) galleries to counteract the enemy's mine attack. A water ditch should serve as a serious defense against an open attack.
The attack of such a fort, as shown by the Russian-Japanese and World Wars (Verdun, Osovets, Przemysl), will be carried out according to the Vauban method by a system of trenches and connecting them, zigzag in terms of moves, messages. The first trench (first parallel) is laid at a distance of 200-1000 m from the fort. Here the infantry is consolidated, and the artillery is trying to suppress the fire of the fort and the fort gaps. When this succeeds, then at night the sappers lay the 2nd parallel (trench) 400 meters from the fort. It is occupied by the infantry, and the sappers, with workers from the infantry, connect the two parallels with communication trenches arranged in a zigzag manner so that each subsequent zigzag goes over the previous knee of the communication passage, thus protecting it from being hit by longitudinal fire. When the passage of the message is excerpted, the workers of the head knee cover themselves with a parapet of earthen bags. For the 2nd parallel arrange the 3rd parallel in the same way, 100-150 meters from the fort. And from here, if the defense of the latter is not broken, sensitive and energetic, they sink underground and go through mine galleries. These galleries are 1.4 m high and 1 m wide. They dress with frames.
The defender is not limited to one fire and the reflection of the assault. Trying to wrest the initiative from the hands of the enemy, he himself arranges parallels in front of his fortifications. These "counter-requests" can be very damaging to the attacker and prolong the siege. They helped the Russians in the defense of Sevastopol (1856/54) and the French in the defense of Belfort in 1870/71.
So concrete and steel fight the cannon and fight with full hope of success, as the world war has shown. Of course, this is only possible if the fortifications are not completely outdated.
It should be noted, however, that they will never or almost never be completely modern, because fortresses are being built slowly and are expensive (150-200 million rubles). And since military budgets are limited, any state is more willing to spend money on new artillery, on tanks, aircraft, etc., than on replacing an outdated fort with a modern one.
But it’s not that bad. And the somewhat outdated fortress also contains great defensive capabilities. It's up to the commandant to deploy them. The last conclusion, as you know, after 12 years was fully confirmed only by the Brest Fortress!
