Carnoustie - Golf Street in the Up direction only, timetabled for 4 minutes in the Down direction presumably as a PPM swizz.
The service in the down direction is timed longer because of an adjustment required by the Train Planning Rules. 2 minutes adjustment time for any train terminating in platform 2, due to approach control. Therefore minus this allowance the journey time is the same as the up direction, 1.5 minutes.