Since approx. 1890 most of the branchline coaches in Bavaria got a Hardy , i. e. a vacuum brake. On mainlines the Westinghouse air brake (called Westinghauser in the railwaymen's slang) was used for passenger trains. Whilst the mainline passenger engines had a pump for creating pressure, the branchline engines got an ejector for generating vacuum, IIRC. The silencer for the exhaust of the hardy brake was placed behind or besides the stack.