CREATE TABLE table_name_4 (prr_class VARCHAR(255), build_date VARCHAR(255), wheel_arrangement VARCHAR(255), service VARCHAR(255))
What is the PRR class of the freight train built in 1967 with a b-b wheel arrangement?
    
SQL: SELECT prr_class FROM table_name_4 WHERE wheel_arrangement = "b-b" AND service = "freight" AND build_date = "1967"