What is the category for trains numbered 16609/16610?
CREATE TABLE table_21716139_1 (category VARCHAR, train_no VARCHAR)
SELECT category FROM table_21716139_1 WHERE train_no = "16609/16610"
### Context: CREATE TABLE table_21716139_1 (category VARCHAR, train_no VARCHAR) ### Question: What is the category for trains numbered 16609/16610? ### Answer: SELECT category FROM table_21716139_1 WHERE train_no = "16609/16610"