21 cars, 90 passengers, 5 bays. 90 seconds on the clock.
90 waiting
You have 90 seconds, starting at your first tap. A bump costs 3 seconds.
Call the cars to the stop in this order: 2, 13, 3, 8, 6, 1, 11, 5, 18, 19, 20, 21, 14, 15, 9, 10, 4, 7, 12, 17, 16.