SELECT SUM(total_produced) FROM table_name_13 WHERE wheel_arrangement = "b-b" AND prr_class = "bs6" AND builder’s_model = "ds-4-4-660"
Berapa total unit yang dibangun dari model DS-4-4-660 dengan pengaturan roda B-B dan kelas PRR BS6?
CREATE TABLE table_name_13 (total_produced INTEGER, builder’s_model VARCHAR, wheel_arrangement VARCHAR, prr_class VARCHAR)