What is the train in front of?
The train is in front of the cars.
     src        edge_attr  dst
0      0   to the left of   24
1      0   to the left of   23
2      0   to the left of   25
3      0  to the right of   21
4      0  to the right of   20
..   ...              ...  ...
116   27  to the right of   28
117   27   to the left of   26
118   28   to the left of   27
119   28   to the left of   19
120   28   to the left of   26

[121 rows x 3 columns]