Alpine Line

Last updated
Alpine Line
Southeastern France
Bloc B1 Rimplas.JPG
Block B1 at Rimplas
TypeDefensive line
Site information
Controlled byFrance
Site history
Built1930–1940
In use1935–1969
MaterialsConcrete, steel
Battles/wars Italian invasion of France, Operation Dragoon, Second Battle of the Alps

The Alpine Line (French : Ligne Alpine) or Little Maginot Line (French: Petite Ligne Maginot) was the component of the Maginot Line that defended the southeastern portion of France. In contrast to the main line in the northeastern portion of France, the Alpine Line traversed a mountainous region of the Maritime Alps, the Cottian Alps and the Graian Alps, with relatively few passes suitable for invading armies. Access was difficult for construction and for the Alpine Line garrisons. Consequently, fortifications were smaller in scale than the fortifications of the main Line. The Alpine Line mounted few anti-tank weapons, since the terrain was mostly unsuitable for the use of tanks. Ouvrage Rimplas was the first Maginot fortification to be completed on any portion of the Maginot Line, in 1928. The Alpine Line was unsuccessfully attacked by Italian forces during the Italian invasion of France in 1940. Following World War II, some of the larger positions of the Alpine Line were retained in use through the Cold War.

Contents

Concept

Block 2, Ouvrage Sainte-Agnes Ouvrage de Sainte-Agnes bloc2.jpg
Block 2, Ouvrage Sainte-Agnès

As France studied measures to protect its northeastern frontier with Germany, a parallel effort was made to examine the improvement of France's defenses against Italy in the southeast. France's Italian border was a relic of the 1860 Treaty of Turin in which the Duchy of Savoy and the County of Nice were incorporated into France. The treaty boundary roughly followed the crest of the Maritime Alps inland through the Cottian Alps to Switzerland. The precise line of demarcation left the upper reaches of many westward-draining valleys in Italian hands, thus giving Italy positions on high points overlooking French territory, those however were most impractical and inadequate.

The region had been extensively fortified in the seventeenth, eighteenth and nineteenth centuries, most notably by Vauban, whose fortifications of Briançon have been designated a UNESCO World Heritage Site, and by Raymond Adolphe Séré de Rivières in the late nineteenth century, who expanded the Fort de Tournoux and other fortifications in the area as part of the Séré de Rivières system of fortifications. [1] Passage through the Alps was possible only at a series of comparatively low passes, and movement toward the major cities of southeastern France such as Lyon, Grenoble or Nice was possible only along a series of deep river valleys. Defenses therefore tended to concentrate in consistent locations:

In 1925 General Charles Nollet, the Minister of War, directed General Jean Degoutte to survey the southeastern frontier and to make recommendations for their defense. Degoutte's proposal used principles of defense in depth to economize on manpower and funds, which were needed for the main Maginot defenses in northeastern France. The still-ambitious plan proposed in 1927 envisioned a series of fortified positions right on the frontier divides at every potential crossing, backed by thirty-six centers of resistance, each with fourteen infantry casemates and twelve infantry shelters, a total of about one thousand blockhouses. Costs were estimated at 250 million francs. [3]

The proposed plan was criticized for placing the fortifications too far forward by the Commission de Defense, but the overall organization was approved by Minister of War (and former Prime Minister) Paul Painlevé, with a strategy of fortifying Menton, Sospel and the valleys of the Vésubie and Tinée. Revisions in late 1927 proposed about 400 positions at a cost of between 400 million and 500 million francs. [4] The plan was altered in 1928 by General Fillonneau, who proposed to concentrate fortifications along potential invasion axes, rather than along a continuous line. The geographic emphasis remained on Menton and Sospel, but the concept of frontal confrontation was replaced by a strategy of attack from the flanks of a potential advance. Fillonneau was assisted by the new management organization for the Maginot fortifications, the Commission d'Organisation des Régions Fortifiés, or CORF. The proposal was estimated to cost 700 million francs to build 103 ouvrages and to reconstruct 28 old fortifications. An initial phase, designed to protect Nice, was estimated to cost 205 million francs [5]

Unlike the relatively thin, linear defenses of the northeast, the revised Alpine fortifications extended some distance back from the frontier, with forward defenses supported by rearward defenses, compartmentalized by the terrain into distinct sectors. A final proposal in 1930 established a scaled-back, prioritized programme of 362 million francs to be executed in two phases, with the second phase to cost an additional 62 million francs. [6]

Description

Avant-poste du Col des Fourches, a typical high Alpine frontier post Avant-poste du col des Fourches.jpg
Avant-poste du Col des Fourches, a typical high Alpine frontier post

As with the main Maginot Line of the northeast, positions took the form of concrete-encased strongpoints linked by tunnels, which housed living quarters, magazines and utilities for the ouvrage. Larger ouvrages were provided with 600 mm (1 ft 11+5⁄8 in) narrow gauge rail lines to move materials and munitions, although unlike the northeastern positions, none were electrified. Because of the mountainous terrain and the vertical character of the sites chosen for fortification, individual blocks typically emerged from rock faces in a steep hillside or cliff with mined galleries within under rock cover. By comparison, most northeastern ouvrages were semi-submerged into the gently rolling soil with galleries deeply buried beneath earth cover. In addition to the linked complexes of blockhouses that formed the grand and petit ouvrages, the country around and between each position was provided with isolated blockhouses, observation points, shelters (or abris), outposts (avants postes) and batteries, using much the same vocabulary of rounded concrete forms as the primary line of fortifications. These positions allowed the use of mobile supporting artillery, and provided rallying and control points for the necessary infantry support in the country between strongpoints, as the security of the border did not and could not depend on subterranean fortifications alone. The disposition of forward outposts, backed by heavier fortifications some kilometers to the rear, provided a defense in depth that was, in the case of the Alpine fortifications, supported by the difficult terrain. [7]

Organization

The Alpine Line (click to enlarge). 1: Fortified Sector of Savoy 2-6: Fortified Sector of Savoy 7-12: Fortified Sector of Dauphine 14-27: Fortified Sector of the Maritime Alps. For a full list and details on the various strong points, see List of Alpine Line ouvrages Alpine Line 10 June 1940.svg
The Alpine Line (click to enlarge).
1: Fortified Sector of Savoy
2–6: Fortified Sector of Savoy
7–12: Fortified Sector of Dauphiné
14–27: Fortified Sector of the Maritime Alps.
For a full list and details on the various strong points, see List of Alpine Line ouvrages

The Alpine Line was divided into three major sectors. From north to south, they were:

In addition, the area to the north of the principal fortifications was organized as the Defensive Sector of the Rhône, with virtually no fixed fortifications, since it faced neutral Switzerland. [11]

The Alpine region was under the overall command of the Army of the Alps, General René Olry in command at Valence. Its chief units were the 14th Army Corps in the SF Savoy and SF Dauphiné, and the 15th Corps in the SF Maritime Alps. [11]

Construction

Work had already begun on Ouvrage Rimplas, which was in fact the first Maginot ouvrage to be built in either the northeast or southeast. The construction contract was signed 7 September 1928 with incomplete plans. [12] Rimplas was a prototype project, not representative of other alpine or Maginot positions. CORF took over responsibility for construction in 1931, standardizing design practices, although each project was closely adapted to local circumstances. [13] Construction was made difficult by poor access, high altitude and a short construction season. In 1931 work commenced at twenty-two sites. [14] In 1932 Ouvrage Cap Martin was sufficiently complete that it could be used in an emergency. [15] Work continued through 1936, even though CORF had been disestablished at the end of 1935. While most of the larger positions were complete, a number of the smaller, higher-altitude positions were never completed in time for war in 1940. From 1939, the main d'oeuvre Militaire (MOM) built a number of positions and blockhouses, usually in locations close to the frontier. [16] Many of the MOM positions were incomplete in 1940. [17]

Compared with the northeastern Maginot positions, the Alpine fortifications made comparatively little use of retracting turrets, using instead concreted casemates in mountainsides surveying prepared fields of fire. The Alpine Line featured relatively few artillery ouvrages, tending instead to use mixed-arms positions that combined artillery casemates and infantry positions. The main fortifications were supported by infantry shelters, or abris, of both the "passive", lightly armed type, and "active" abris with heavier armament. Some of the mountaintop gros ouvrages used aerial tramways for their primary means of access. Military roads were often constructed in the absence of existing access. All of the large positions were provided with subterranean barracks and central utility plants. [18] Nearly all fortifications were excavated from solid rock. Coverage could therefore be reduced compared to the ouvrages of the northeast, which were at depths of up to 30 metres (98 ft) in deep soil to resist heavy siege artillery. [19] Independent means of power generation were a necessity in the absence of a utility distribution system. Likewise, telephone communication was problematic, with many positions using line-of-sight optical semaphores for communication. [20]

June 1940

Like the main Maginot Line did with the Germans, the Alpine Line achieved the goal of preventing the Italians from advancing through the protected areas. And, as the Italians had no alternative but to directly confront the fortifications, the south of France was completely protected from the Italian advance. An advance along the main coastal road was delayed by stiff resistance at the Casemate du Pont Saint Louis on the border at Menton, which was manned by seven men led by a non-commissioned officer and was supported by main-line fortifications at Ouvrage Cap Martin. [21] [22] A direct assault on Cap Saint Martin was suppressed by the ouvrage itself, supported by artillery fire from Ouvrage Mont Agel. [23]

Two more attacks were mounted, in the areas of Briançon and the Little St Bernard Pass, with little effect due to weather and the difficult terrain. Positions in the high Alps were shelled by Italian forces but were not directly attacked. Ouvrage Barbonnet traded fire with Italian positions prior to the armistice of 25 June 1940.

Vallo Alpino

The Italian counterpart to the Alpine Line was Italy's Alpine Wall (Vallo Alpino), the western portions of which faced the Alpine Line across the Alpine Valleys.

See also

Related Research Articles

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<span class="mw-page-title-main">Ouvrage Sapey</span> Work of Maginot Lines Alpine extension

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<span class="mw-page-title-main">Ouvrage Janus</span>

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Ouvrage Plate Lombard is a lesser work of the Maginot Line's Alpine extension, the Alpine Line. The ouvrage consists of one entry block, two infantry blocks and one observation block. Unusually for an ouvrage, Plate-Lombard was built by MOM, which usually was responsible for lesser fortifications. The isolated position was commanded in 1940 by Lieutenant de Loye. It controlled the Fouillouse valley and the Col du Vallonet.

<span class="mw-page-title-main">Ouvrage Saint Ours Bas</span>

Ouvrage Saint Ours Bas is a lesser work of the Maginot Line's Alpine extension, the Alpine Line. The ouvrage consists of one infantry block. The location is unusual in lacking the underground galleries typical of a Maginot fortification, making it more like a blockhouse than an ouvrage. It was armed with two machine gun cloches and three heavy twin machine guns and six light machine gun embrasures. The interior is laid out on two levels.

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<span class="mw-page-title-main">Ouvrage Saint-Roch</span>

Ouvrage Saint-Roch is a work of the Maginot Line's Alpine extension, the Alpine Line, also known as the Little Maginot Line. Small for a gros ouvrages, the ouvrage consists of one entry block, one artillery block and two observation blocks overlooking Sospel at an altitude of 426 metres (1,398 ft). The position is located just to the southwest of Sospel, its entrance block in a narrow valley and the artillery block on the other side of the ridge overlooking Sospel. The ouvrage is laid out along a single line, with the entry block to the rear, immediately followed by the usine, with barracks farther along and Blocks 2 and 3 at intervals. The position's main armament is concentrated in Block 4, a massive blockhouse designed to protect against rockfalls from higher up the mountain.

Ouvrage Barbonnet is a work of the Maginot Line's Alpine extension, the Alpine Line, also called the Little Maginot Line. The ouvrage consists of one entry block and one infantry block facing Italy. The ouvrage was built somewhat behind the main line of fortifications on the old Fort Suchet, which was already armed with two obsolete Mougin 155 mm gun turrets.

Ouvrage Roquebrune is a work of the Maginot Line's Alpine extension, the Alpine Line. The ouvrage consists of one entry block, two artillery blocks and one observation block facing Italy. The fortification is located on the heights behind Roquebrune at an elevation of 321 meters overlooking Cap Martin and the bays of Roquebrune and Menton. The ouvrage was manned by 293 men of the 58th Demi-Brigade Alpin de Forteresse (DBAF), supported by the 157th Régiment d'Artillerie de Position (RAP), under the command of Captain Gayot.

<span class="mw-page-title-main">Ouvrage Cap Martin</span> Fortification in France

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<span class="mw-page-title-main">Ouvrage Sainte-Agnès</span>

Ouvrage Sainte-Agnès was a work of the Maginot Line's Alpine extension, the Alpine Line, also called the Little Maginot Line. The fortification was built between 1932 and 1938. The site is at the south edge of the hill town of Sainte-Agnès, Alpes-Maritimes at an elevation of 780 metres overlooking the Mediterranean Sea.

<span class="mw-page-title-main">Fortified Sector of Montmédy</span>

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The Fortified Sector of Flanders was the French military organization that in 1940 controlled the section of the French border with Belgium between Lille and the North Sea. The sector was part of a system of fortifications that, in other sectors, included the Maginot Line. In the case of the Flanders sector, no large fortifications of the kind typified by the Maginot Line were built in the area. Fortifications were confined to almost two hundred blockhouses built during the 1930s, and some defensive inundations in the vicinity of Dunkirk. The Fortified Sector of Flanders was bordered on the east by the Fortified Sector of Lille It was quickly overrun by German forces during the Battle of France.

<span class="mw-page-title-main">Fortified Sector of the Dauphiné</span>

The Fortified Sector of the Dauphiné was the French military organization that in 1940 controlled the section of the Alpine Line portion of the Maginot Line facing Italy in the vicinity of Briançon. By comparison with the integrated defenses of the main Maginot Line, or even of the Fortified Sector of the Maritime Alps to the south, the Dauphiné sector consisted of a series of distinct territories that covered two main invasion routes into France: the route from Turin over the Col de Montgenèvre to Briançon and Grenoble, and the route from Coni over the Col de Larche to Barcelonette and Gap. The sector was the scene of probing attacks by Italian forces during the Italian invasion of France in 1940, in which the French defenses successfully resisted Italian advances until the June 1940 armistice that granted Italy access to southeastern France.

<span class="mw-page-title-main">Fortified Sector of Altkirch</span> Former French military organization

The Fortified Sector of Altkirch was the French military organization that in 1940 controlled the section of the French frontier with Germany and Switzerland in the vicinity of Basel.It was built by France following the First world war from 1928 - 1940. it was built under the mandate of André Maginot, the then minister of war. The sector's principal defense against an advance from Germany was the Rhine itself, which could be crossed only by boat or by seizing a bridge crossing. The frontier with Switzerland was not regarded as a high-risk location, save for a possible advance by German forces through Switzerland. Originally planned as a full extension of the Maginot Line with artillery ouvrages, the sector's fortifications were scaled back and chiefly took the form of casemates and blockhouses. The SF Altkirch adjoined the Fortified Sector of Mulhouse to the north and the Fortified Sector of Montbéliard to the west.

<span class="mw-page-title-main">Fortified Sector of the Vosges</span>

The Fortified Sector of the Vosges was the French military organization that in 1940 controlled the section of the Maginot Line at the northern end of the Vosges Mountains in northeastern France. The sector was bordered to the west by the Fortified Sector of Rohrbach and to the east by the Fortified Sector of Haguenau. The sector featured two gros ouvrages mounting heavy artillery at either end of the sector and one petit ouvrage mounting infantry weapons, linked by a line of casemates. The sector was attacked in 1940 by German forces in the Battle of France. German forces penetrated the casemate line and moved behind French lines. Despite the withdrawal of the mobile forces that supported the fixed fortifications, the three ouvrages successfully fended off German assaults before the Second Armistice at Compiègne, but were unable to hinder German activities to their south. The positions and their garrisons finally surrendered on 1 July 1940. Following the war several positions were reactivated for use during the Cold War. One position, Ouvrage Four-à-Chaux, is open to the public and may be visited.

The Fortified Sector of the Sarre was the French military organization that in 1940 controlled the section of the Maginot Line on either side of the Sarre river. The sector's defenses relied primarily on a system of inundations that could be created by fortified dikes and regulating weirs, backed by blockhouses. Weakly defended compared with other sections of the Maginot Line, the sector received a measure of attention and funding from the mid-1930s when the formerly demilitarized Saarland was reintegrated into Germany. However, with a single petit ouvrage it remained a weak point in the Line. In 1940 the Sarre sector was attacked by German forces in the Battle of France. The inundations were only partly successful, and German forces were able to pierce the Maginot Line at the Sarre, allowing German divisions to move behind the main French line.

<span class="mw-page-title-main">Defensive Sector of the Rhône</span> French military organization

The Defensive Sector of the Rhône was the French military organization that in 1940 controlled the section of the French border with Switzerland and Italy in the area of Geneva. The area was not regarded as a likely point of invasion, owing to the neutrality of Switzerland and the extremely difficult terrain along the Italian portion of the border. It was therefore lightly fortified. Its chief fortified position was the 19th-century Fort l'Écluse, manned by a small force, which held its strategic position against a Panzerkorps for a week in June 1940.

<span class="mw-page-title-main">Defensive Organization of Corsica</span>

The Defensive Organization of Corsica was the French military organization that in 1940 was responsible for the defense of the French island of Corsica against a potential invasion by Fascist Italy. As part of the overall effort to fortify France's borders which included the Maginot Line, the fixed Corsican defenses were constructed in parallel with the Maginot Line, using the same organizational structure and similar designs, albeit scaled back in size, cost and fighting power. The Corsican defenses were designed to deter an Italian landing on the south end of Corsica, and to support artillery batteries capable of controlling the Strait of Bonifacio between Corsica and the Italian island of Sardinia, separated by only twelve kilometers. As World War II unfolded, no attempt was made by Italian forces to mount an opposed landing on Corsica. The island was instead occupied in November 1942. In 1943 Corsica saw fighting when German forces moved from Sardinia. Most of the fortified positions remain to the present day.

<span class="mw-page-title-main">Fortified Sector of Savoy</span>

The Fortified Section of Savoy(Secteur fortifié de la Savoie) was the French military organization that in 1940 controlled the section of the Alpine Line portion of the Maginot Line facing Italy in the Savoy region. The sector constituted part of the Alpine Line portion of the Maginot Line, between the Defensive Sector of the Rhône to the north, and the Fortified Sector of the Dauphiné to the south. The works combined a number of pre-1914 fortifications with Maginot-style ouvrages, with many forward-positioned cavern-style frontier stations or avant-postes that proved effective in holding invading forces near the order.

References

  1. ↑ Mary, Tome 4, pp. 4–6
  2. ↑ Mary, Tome 4, pp. 5–6
  3. ↑ Mary, Tome 4, p. 8
  4. ↑ Mary, Tome 4, p. 9
  5. ↑ Mary, Tome 4, pp. 10–11
  6. ↑ Mary, Tome 4, pp. 13–14
  7. ↑ Mary, Tome 4, p. 34
  8. ↑ Mary, Tome 5, pp. 8–22
  9. ↑ Mary, Tome 5, pp. 23–44
  10. ↑ Mary, Tome 5, pp. 45–73
  11. 1 2 Mary, Tome 5, pp. 4–5
  12. ↑ Mary, Tome 4, p. 16
  13. ↑ Mary, Tome 4, p. 18
  14. ↑ Mary, Tome 4, p. 19
  15. ↑ Mary, Tome 4, p. 23
  16. ↑ Mary, Tome 4, pp. 24–25
  17. ↑ Mary, Tome 4, p. 33
  18. ↑ Mary, Tome 4, pp. 42–62
  19. ↑ Mary, Tome 2, p. 117
  20. ↑ Kauffmann, pp. 66–67
  21. ↑ Mary, Tome 4, p. 29
  22. ↑ Horne, Alistair; To Lose a Battle: France 1940. p. 565 ISBN   978-0-14-013430-8
  23. ↑ Puelinckx, Jean; Aublet, Jean-Louis; Mainguin, Sylvie (2010). "Mont Agel (forteresse du)". Index de la Ligne Maginot (in French). fortiff.be. Retrieved 25 January 2010.

Bibliography

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