In order to make a circular track, the narrow gauge train has an extension into the loft store. It’s not very pretty because it will never normally be seen…
The extension is normally fully enclosed, which should help keep dust out:
The first of the narrow gauge track has now been installed.
The two ends going into tunnels through the wall will eventually be joined up behind the wall, creating a loop. The left hand branch from the point will eventually wander off through the goods yard towards the main tunnel, which you can just see on the far right of this photo: