These coaches were the first of the Stanier period gangwayed designs, having shallow single element sliding window vents and retaining torpedo roof vents. These non-standard features were seen also in the contemporary brake composites to D1850. Like the later D1905 the toilet was in the centre of the coach next to the guard’s van with the tank filler pipes running along the roof. As general service coaches they were seen throughout the LMS and BR(LMR).
Three were converted in 1955 for push-pull working (Comet Models M62DK), but were not given a separate diagram number.