Sperrstelle Trin, Military fortress and museum in Trin, Switzerland.

Sperrstelle Trin (army designation Sperre Nr. 1205) lies west of Trin on the old road from Chur into the Vorderrheintal, between Tamins and Flims. Its main work is an infantry cavern (A 7762) cut into the rock of Crap Sogn Barcazi and Crap Pign on three floors linked by 300 stairs and tunnels, armed with four machine guns and two light machine guns for a crew of 30. Nearby stand a terrain anti-tank obstacle with humps, rails and a tank wall, plus bunkers disguised as a water reservoir, a wooden barn and a forest hut.

Built by civilian contractors in 1941–1943, Sperrstelle Trin was the last blocking position before the Reduit, meant to stop an enemy from entering the Gotthard fortress area. The main infantry work A 7762 was carved into the rock of Crap Sogn Barcazi and Crap Pign in 1941–1942 on three floors linked by 300 steps and tunnels. The position was manned by Mountain Infantry Regiment 18, reserve of Mountain Army Corps 3.

The site is run by the Verein Sperre Trin, founded in October 2009 to maintain the defences. Guided tours cover the rock works in Crap Sogn Barcazi and Crap Pign, the bunkers Porclas Nord, West and Strasse, and the kitchen of the Festungswachtkorps. From December to March a tour called Festung & Fondue visits two bunkers and ends with fondue.

The museum opens several times a month from May to October; guided tours cover the rock works in Crap Sogn Barcazi and Crap Pign plus the Porclas Nord, West and Strasse bunkers. From December to March a "Festung & Fondue" tour visits two bunkers and ends with fondue. Entry today is through the emergency exit, as the former main entrance is closed.

The infantry work's cable car, the Z312, was the only works cable car in an infantry fortification in Graubünden. The site also holds a 12-cm fortress mortar built in 1988, decades after the 1941–1943 bunkers, and the former main entrance is now closed, so visitors enter through the emergency exit.