CREATE TABLE table_name_73 (entered_service INT, builder VARCHAR, number VARCHAR)

When did the tom smith built train enter service with a number under 7007?
SELECT AVG(entered_service) FROM table_name_73 WHERE builder = "tom smith" AND number < 7007
SELECT AVG("entered_service") FROM "table_name_73" WHERE "builder" = "tom smith" AND "number" < 7007