Table: train_production
Columns: fiscal_year
2_car_sets
4_car_sets
6_car_sets
8_car_sets
total_vehicles

Question: What is the smallest 8-car sets if 4-car sets is 47?
SQL: SELECT MIN("8_car_sets") FROM train_production WHERE "4_car_sets" = 47

Question: What is the largest 6-car-sets for fiscal year 1968?
SQL: SELECT MAX("6_car_sets") FROM train_production WHERE "fiscal_year" = 1968

Question: What is the lowest fiscal year if total vehicles is 490?
SQL: SELECT MIN("fiscal_year") FROM train_production WHERE "total_vehicles" = 490