Sperrstelle Schrattenfluh, Military fortification in Flühli, Switzerland.

The Sperrstelle Schrattenfluh is a World War II army barrier in Flühli, canton Lucerne, built 1941–1944 by the 8th Division. Its backbone was three infantry works — Warmendossen, Felskopf and Blaufels — each manned by 43 men in 1944, with a three-row anti-tank obstacle (GPH Flühli T 1414) and the Gloggenmatt observation post with steel bell.

The Flühli position was built by the 8th Division from 1941 to 1944, with construction at the Felskopf fortress begun in 1941 by civilian firms and completed in 1944 at a cost of 3.3 million francs, 1.9 million of it for the works. Together with the Hirsegg position behind it, it formed the strongest blocking position in the 8th Division's area. The three infantry works Warmendossen, Felskopf and Blaufels were the backbone, each manned by 43 men in 1944. The installations were disarmed in 1991 and declassified in 2001.

The site lies in the Mariental plain south of Flühli, where around 370 men blocked the route toward Sörenberg, Glaubenbielen and Giswil. At Bunihus a barrack village housed the soldiers, and the concrete humps by the Rotbach were cast there. The three infantry works Warmendossen, Felskopf and Blaufels formed the backbone, each manned by 43 men in 1944.

The site lies in the Mariental near Flühli, canton Lucerne, not at Marbach. The three infantry works Warmendossen, Felskopf and Blaufels formed its backbone; the works were disarmed in 1991 and released from secrecy in 2001. The installations are largely preserved and partly protected, so enter only where access is open.

The Flühli position was declassified only in 2001, decades after its guns were removed in 1991. Its three infantry works — Warmendossen, Felskopf and Blaufels — each had a crew of 43 men in 1944, with their own emergency power unit, collective gas protection and water supply. Look for the observer post Gloggenmatt A 2352 with its steel bell.