Table schema:
CREATE TABLE table_12791809_1 (super_b_capacity_reached_ VARCHAR, _citation_needed_ VARCHAR, freight_carried_s_tonne VARCHAR)

Question: When was the super b capacity reached when the freight carried s tonne was 198818?
SQL: SELECT super_b_capacity_reached_[_citation_needed_] FROM table_12791809_1 WHERE freight_carried_s_tonne = 198818