I think there are a few of us that would be interested in what 3D LNWR wagon components were available, either stl files for printing at home or fully printed for purchase. I'm currently staring at drawings for a CCT and LNWR axleboxes trying to decide where to start drawing out - springs or axleboxes.
Don't forget that CCTs were classed by the LNWR as carriage stock and built at Wolverton, rather than goods stock which was built at Earlestown. Best source of detail information from that era is probably Millard's WCJS, published by the HMRS, but even then its sparse.
Regarding the short ballast wagon, as the modellers drawing has PWD lettering it was probably done from a Crewe official photo of the Crewe deviation lines being built. I don't know of an official drawing and it does not appear in the 1903 diagram book, but is in the DNGR diagram book, so the dimensions from that are probably correct, except for the width!
lnwrhg.com
Mike