Question: What is the year retired of the locomotive which had the quantity made of 25?
SQL: SELECT "Year(s) retired" FROM "2-18620528-7" WHERE "Quantity made" = '25';

Question: Which class had a quantity made of 20?
SQL: SELECT "Class" FROM "2-18620528-7" WHERE "Quantity made" = '20';

Question: What is the locomotive class that has a wheel arrangement of 2-8-2 and a quantity made of 25?
SQL: SELECT "Class" FROM "2-18620528-7" WHERE "Wheel arrangement" = '2-8-2' AND "Quantity made" = '25';

Question: What is the quantity preserved to the locomotive with a quantity made of 6?
SQL: SELECT "Quantity preserved" FROM "2-18620528-7" WHERE "Quantity made" = '6';