CREATE TABLE table_21415 ("Departure" TEXT, "Going to" TEXT, "Calling at" TEXT, "Arrival" TEXT, "Operator" TEXT)

Name the number of going to for thurlby, braceborough spa at departure being 16.50
SELECT COUNT("Going to") FROM table_21415 WHERE "Calling at" = 'Thurlby, Braceborough Spa' AND "Departure" = '16.50'
SELECT COUNT("Going to") FROM "table_21415" WHERE "Calling at" = 'Thurlby, Braceborough Spa' AND "Departure" = '16.50'