Question: Name the number of going to for  thurlby, braceborough spa at departure being 16.50
Schema: create table table_17200372_2 (going_to varchar, calling_at varchar, departure varchar, PRIMARY KEY (going_to))
SQL: select count(going_to) from table_17200372_2 where calling_at = "thurlby, braceborough spa" and departure = "16.50"