user: ### NOW ANSWER:
Question: When did the Tom Smith built train enter service with a number under 7007?
Columns: ['Number', 'Locomotive type', 'Wheel arrangement', 'Builder', 'Entered Service', 'Withdrawn']
Types: ['real', 'text', 'text', 'text', 'real', 'real']
Sample row: [1.0, 'Steam', '0-4-2 Tank', 'Jubb Engineering', 1922.0, 1928.0]
SQL:

assistant: SELECT AVG("Entered Service") FROM "Table" WHERE "Builder" = 'Tom Smith' AND "Number" < 7007.0;