The Combined Nomenclature (CN), v1:2018
8606 91: Railway or tramway goods vans and wagons, covered and closed (excl. self-discharging goods vans and wagons and tank wagons and the like)
https://www.dst.dk/en/Statistik/dokumentation/nomenklaturer/kn?id=97dd4f6e-1b47-43b5-8532-380d3d1b7c2f