From the thread in the forum Stummis Modellbahnforum:
A German modular layout, an example on how you can have narrow curves but the staging and the theme you chose are such that the general impression is not disturbed by that compromise:
The effect is cleverly achieved thanks to the vegetation near the line that accompanies the tracks and trains, giving the impression of supporting the railway wagons. If the vegetation were lacking, especially on the inner side, it would appear that the train was about to go limp and fall on the inner side of the tracks.
Short locomotives, shunters, and 2 axis boxcars are suggested. Another picture from above: