Are these trucks or trains?
These are trains.
    src        edge_attr  dst
0     0  to the right of    7
1     0  to the right of   13
2     1  to the right of    2
3     1  to the right of    7
4     1  to the right of    4
..  ...              ...  ...
85   25   to the left of   26
86   25  to the right of   21
87   26  to the right of   21
88   26  to the right of   25
89   26   to the left of   22

[90 rows x 3 columns]