After arriving at Long Marston 108 minutes early with the 5D94 08:30 Cardiff Canton to Long Marston ECS on 29 July 2017, 143606 changes direction and commences to run round the complex's perimeter line, while a worker closes the gates behind it. Behind the unit is a rake of bogie oil tankers that was booked to leave the depot later in the day as the 6E66 17:14 Long Marston to Peterborough, behind a GBRf Class 66, but in the event did not run.