Zwischenwerk IV b

Gazing upon Zwischenwerk IV b, one might initially see only overgrown ruins. But beneath the tangled vegetation lies a unique story. Zwischenwerk IV b, nestled in Cologne’s Vogelsang district, holds a special place in the city’s fortifications. Its distinct design stems from a peculiar circumstance. In the 1870s, six armored turrets became available for fortress integration. A decision was made for a decentralized approach, with one turret finding its home here at Zwischenwerk IV b. The exact reason for this choice, along with the precise installation date, remains a mystery. Zwischenwerk IV b distinguished itself from other large Zwischenwerke in Cologne’s outer fortification ring. Its broken front, two identical shoulder caponiers designed solely for flanking fire, and a gorge similar to Cologne’s forts east of the Rhine made it resemble a small, self-contained fort. The larger gorge barracks followed the usual design. The oversized pointed caponier, designed to cover the front ditches and house the armored turret, added another unique element. Post-1885 renovations saw the removal of traverses and gun platforms from the wall, replaced by typical rifle positions along the firing line. The front ditch defense shifted from the escarpment to the counterscarp side. An armored observation tower, not present in earlier designs, likely appeared after 1890. Zwischenwerk IV b boasted impressive dimensions. It measured 186 meters wide and 110 meters deep, exceeding the size of a typical “large” Zwischenwerk in the Cologne belt. The ditch, about 6.5 meters deep, sloped up to 3.5 meters near the gorge barracks. Following the 1885 modifications and reinforcements, the walls and ceilings generally consisted of one meter of masonry, one meter of sand, and 1.2 meters of concrete. In particularly vulnerable areas, this was increased to 3 to 4 meters of concrete. Originally, the armament plan called for two 9 cm cannons in each shoulder point. The turret housed two 15cm ring cannons. Zwischenwerk IV b’s construction, excluding the turret, took place between 1875 and 1877. The complete work was likely finished by 1881. It was ultimately decommissioned between January 19th and November 28th, 1921. Even in its current state, Zwischenwerk IV b silently tells a tale of strategic decisions, innovative design, and a bygone era of military might.