This layout modelled on a section of Locomotion uses 4 scales to create forced perspective, which I think is really clever.
The 2 lines in the foreground are O gauge, the tracks with the 2 brake vans on and the covered L&MR open coach are is OO and the track with the open wagon on, (behind the brake van), is TT. Finally, the track with the Class 08 and the Queen Mary brake van on at the rear of the layout is N!