Question: What's the sum of Quantity for the Class of 1928 of Ci-30?
SQL: SELECT SUM("Quantity") FROM "2-18734371-3" WHERE "Class from 1928" = 'Ci-30';

Question: What Class to 1928 has the Quantity smaller than 440 and Seats of 29/29?
SQL: SELECT "Class to 1928" FROM "2-18734371-3" WHERE "Quantity" < 440.0 AND "Seats" = '29/29';