NER P7 8 plank 20 ton coal hopper wagon
Built in large numbers from 1903, using same chassis as p6 wagons, extending hopper upwards to maximum that would fit under loading screens.
In 1929 there were over 13000 still in use.
used around the coalfield pitheads in north east England.
After use on the mainlines many ended up on internal industrial railways.
requires wheels and finishing
HO scale(1/87 3.5mm/ft)
more 3d printed models from Recreation21 here
https://www.rue-d-etropal.com/3D-printing/3d_printed_designs.htm