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 train ( ObjectNumber VARCHAR, Railway_ID VARCHAR )
TABLE: CREATE TABLE railway ( ObjectNumber VARCHAR, Railway_ID VARCHAR )

### Question ###
List the object number of railways that do not have any trains.

### Accurate SQL ###

SELECT ObjectNumber FROM railway WHERE NOT Railway_ID IN (SELECT Railway_ID FROM train)