Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_56212 ( "Number" real, "Locomotive type" text, "Wheel arrangement" text, "Builder" text, "Entered Service" real, "Withdrawn" real )

### Question ###
When did the tom smith built train enter service with a number under 7007?

### Accurate SQL ###

SELECT AVG("Entered Service") FROM table_56212 WHERE "Builder" = 'tom smith' AND "Number" < '7007'