In the gameplay stream, the trains that terminated at Stonebridge Park were parked in the wrong siding. In the stream, a train was parked in the siding that is labelled number 47 on this map (not sure if the numbers are correct), but in real life they stop in siding 21 or 22 just outside the station.
It may have been a train, albeit with passengers onboard, leaving the actual depot. I know on the driver training videos, it is shown how to use the siding the train was in on the live stream.
Looking at your picture again, 21 and 22 aren’t sidings but the in and out lines for the depot. The train wash is located on line 21 as it enters the depot. You can see it on Google Maps above and in this YouTube video...
That's strange because I'm sure I've seen trains park there after terminating at the station and then leaving on its next service. () In this video at about 4:30, you can see a train doing this, although you don't see it leave the siding afterwards.
They may well turnaround there too so as to avoid going through the train wash, but I don’t know. All I know is what I’ve seen in the driver training videos which shows lines 21 and 22 as the in/out lines and 46/47 as the turnaround sidings. Maybe someone with much more knowledge of the route will be able to clarify things.
