Do you see both carts and fences?
No, there is a fence but no carts.
    src        edge_attr  dst
0     0   to the left of   19
1     0   to the left of   17
2     0   to the left of    4
3     0  to the right of    8
4     0               on    2
..  ...              ...  ...
58   18   to the left of   11
59   19   to the left of    4
60   19  to the right of    0
61   19  to the right of    2
62   19  to the right of    8

[63 rows x 3 columns]