Railway or tramway sleepers (cross-ties) of wood, impregnated

CPC v2.1 class (Railway or tramway sleepers (cross-ties) of wood, impregnated) within 'Wood in the rough, treated with paint, stains, creosote or other preservatives; railway or tramway sleepers (cross-ties) of wood, impregnated; hoopwood, split poles, wooden sticks and the like'. UN Central Product Classification grouping of related products at this level.