From its pseudo-CIWL livery and paper signs "Reserviert B & B" in the windows, it looks as if this one could belong to Brenner & Brenner. Some technical data from the inscriptions: 140 km/h, 48 t empty mass, 48 seats, brake O-PR, home station Wien Südbahnhof, last revision Wb 21.1.05, length 23.50 m, bogie distance 16.18 m.
Meanwhile I got the information: It's probably the WR4ü-28 Mitropa 1061 (built by LHB 1930), DRB 199 234, used by the Soviets after 1945, later rebuilt to ÖBB measuring car 952 200 (80 81 972 6 020-7), 1992 stored in Innsbruck, 1998 sold to B & B.