Question: What is Name, when Builder is "Kerr Stuart"?
SQL: SELECT "Name" FROM "2-1820430-1" WHERE "Builder" = 'Kerr Stuart';

Question: What is Built, when Works Number is "717"?
SQL: SELECT "Built" FROM "2-1820430-1" WHERE "Works Number" = '717';

Question: What is Type, when Works Number is "unknown"?
SQL: SELECT "Type" FROM "2-1820430-1" WHERE "Works Number" = 'unknown';