Question: Which year has a railway class of 250?
SQL: SELECT "Year" FROM "2-15203881-1" WHERE "Class" = '250';

Question: Which works number has a class of 15th and year of 1940?
SQL: SELECT "Works no." FROM "2-15203881-1" WHERE "Class" = '15th' AND "Year" = '1940';

Question: Which builder has a railway of Rhodesia Railways?
SQL: SELECT "Builder" FROM "2-15203881-1" WHERE "Railway" = 'Rhodesia Railways';

Question: Which railway has a class of 250 and year 1936?
SQL: SELECT "Railway" FROM "2-15203881-1" WHERE "Class" = '250' AND "Year" = '1936';