if (amount != 0) {

				if (new_cid != v->cargo_type) {

					cost.AddCost(GetRefitCost(v->engine_type));

				}

				num += amount;

				if (flags & DC_EXEC) {

					v->cargo.Truncate((v->cargo_type == new_cid) ? amount : 0);

					v->cargo_type = new_cid;

					v->cargo_cap = amount;

					v->cargo_subtype = new_subtype;

					InvalidateWindow(WC_VEHICLE_DETAILS, v->index);

					InvalidateWindow(WC_VEHICLE_DEPOT, v->tile);

					InvalidateWindowClassesData(WC_TRAINS_LIST, 0);

				}