Alpine Line - Construction

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. 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. Construction was made difficult by poor access, high altitude and a short construction season.In 1931 work commenced at twenty-two sites. In 1932 Ouvrage Cap Martin was sufficiently complete that it could be used in an emergency. 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 1937, the main d'oeuvre Militaire (MOM) built a number of light positions and blockhouses, usually in locations close to the frontier. Many of the MOM positions were incomplete in 1940.

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. 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. 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.