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These pockets are drawn from measured dimensions of actual pockets on preserved railway equiment from the 1910s and 1920s. They are beefed up to print properly, but most of the "beef' is hidden in the thickness of the pocket, so the external dimensions are correct. I have also not modelled the inside of the triangular dart.
The original cars came with 22 or 26 pockets so these sets are good for 4 cars, plus spares.