Statfold Barn (near Tamworth) have a dual gauge out-and-back line with a reversing loop where the Shared rail swaps sides half way round the loop. My photo of the track at the swap-over position disappeared in a computer crash!

It's a popular outfit, there must be other RMwebbers who have photographed this track feature.??

It would be possible to copy the side-to-side swap at the middle of your cassette length.