Maginot Line - Organization

Organization

Although the name "Maginot Line" suggests a rather thin linear fortification, the line was quite deep, varying in depth (i.e., from the border to the rear area) from between 20 to 25 kilometres (12 to 16 miles). It was composed of an intricate system of strong points, fortifications, and military facilities such as border guard posts, communications centres, infantry shelters, barricades, artillery, machine gun, and anti-tank gun emplacements, supply depots, infrastructure facilities, observation posts, etc. These various structures reinforced a principal line of resistance, made up of the most heavily armed "ouvrages", which can be roughly translated as fortresses or major defensive works.

From the front and proceeding to the rear, the line was composed of:

• Border Post line (1): This consisted of blockhouses and strong houses which were often camouflaged as inoffensive residential homes, built within a few metres of the border, and manned by troops so as to give alarm in the event of sneak or surprise attack as well as delay enemy tanks with prepared explosives and barricades.

• Outpost and Support Point line (2): Approximately 5 kilometres (3 miles) behind the border, a line of anti-tank blockhouses were intended to provide resistance to armoured assault sufficient to delay the enemy so as to allow the crews of the "C.O.R.F. ouvrages" to be ready at their battle stations. These outposts covered major passages within the principal line.

• Principal line of resistance (3): This line began 10 kilometres (6 miles) behind the border. It was preceded by anti-tank obstacles which were metal rails planted vertically in 6 rows with heights varying from 0.70 to 1.40 metres (2 ft 4 in to 4 ft 7 in) and buried to a depth of 2 metres (6 ft 7 in). These anti-tank obstacles extended from end to end in front of the major works across hundreds of kilometres (miles), interrupted only by extremely dense forests, rivers, or other nearly impassable terrain.

The anti-tank obstacle system was immediately followed by an anti-personnel obstacle system made primarily of very dense barbed wire. Anti-tank road barriers also made it possible to block roads at necessary points of passage through the tank obstacles.

• Infantry Casemates (4): These bunkers were armed with twin machine-guns (abbreviated as JM in French) and anti-tank guns of 37 or 47 mm (1.5 or 1.9 in). They could be single (with only one firing room in only one direction) or double (two firing rooms, in 2 opposite directions). These generally had 2 floors, with a firing level and a support/infrastructure level that provided the troops with rest and services (power generating units, reserves of water, fuel, food, ventilation equipment, etc.). The infantry casemates often had 1 or 2 "cloches" or turrets located on top of them. These GFM cloches sometimes were used to emplace machine guns or observation periscopes. Their crew was 20 to 30 men.

• Petits ouvrages (5): These small fortresses reinforced the line of infantry bunkers. The petits ouvrages were generally made up of several infantry bunkers connected by an underground tunnel network to which were attached various buried facilities, such as barracks, electric generators, ventilation systems, mess halls, infirmaries, and supply caches. Their crew consisted of between 100 and 200 men.

• Ouvrages (6): These fortresses were the most important fortifications on the Maginot Line, having the sturdiest construction and the heaviest artillery. These were composed of at least six "forward bunker systems" or "combat blocks", as well as two entrances, and were interconnected via a network of underground tunnels that often featured narrow gauge electric railways for transport between bunker systems. The various blocks contained necessary infrastructure such as power stations with generating units, independent ventilating systems, barracks and mess halls, kitchens, water storage and distribution systems, hoists, ammunition stores, workshops, and stores of spare parts, food, etc. Their crews ranged from 500 to more than 1000 men.

• Observation Posts (7) were located on hills that provided a good view of the surrounding area. Their purpose was to locate the enemy and direct and correct the indirect fire of artillery from the artillery fortifications as well as to report on the progress and position of key enemy units. These are large reinforced buried concrete bunkers, equipped with armoured turrets containing high-precision optics that were connected with the other fortifications by field telephone and wireless transmitters (known in French by the acronym T.S.F.).

• Telephone Network (8): This system connected every fortification in the Maginot Line, including bunkers, infantry and artillery fortresses, observation posts, and shelters. Two telephone wires were placed parallel to the line of fortifications, providing redundancy in the event of a wire getting cut. There were places along the cable where dismounted soldiers could connect to the network.

• Infantry Reserve Shelters (9): These were found between 500 and 1,000 metres (1,600 and 3,300 feet) behind the principal line of resistance. These were buried concrete bunkers designed to house and shelter up to a company of infantry (200 to 250 men), and had such features as electric generators, ventilation systems, water supplies, kitchens and heating, which allowed their occupants to hold out in the event of an attack. They could also be used as a local headquarters and as a base from which to carry out counter-attacks.

• Flood Zones (10) were natural basins or rivers that could be flooded on demand and thus constitute an additional obstacle in the event of an enemy offensive.

• Safety Quarters (11) were built near the major fortifications in order to make it possible for fortress ("ouvrage") crews to reach their battle stations within the shortest possible time in the event of a surprise or sneak attack during peacetime.

• Supply depots (12).

• Ammunition dumps (13).

• Narrow Gauge Railway System (14): A network of 600 mm (1 ft 11 5⁄₈ in) narrow-gauge railways was built so as to rearm and resupply the major fortresses ("ouvrages") from supply depots up to 50 kilometres (31 miles) away. Petrol-engined armoured locomotives pulled supply trains along these narrow-gauge lines. (A similar system was developed with armoured steam engines back in 1914–1918.)

• High-voltage Transmission Lines (15), initially above-ground but then buried, and connected to the civil power grid, provided electric power to the many fortifications and fortresses.

• Heavy rail artillery (16) was hauled in by locomotives to predesignated locations so as to support the pre-emplaced artillery located in the fortresses, which was intentionally limited in range to 10–12 kilometres (6–7 miles).