What kind of vehicle is the flag before?
The flag is in front of the train.
    src        edge_attr  dst
0     0  to the right of    1
1     0            above   10
2     1          next to   11
3     1   to the left of    5
4     1  to the right of   11
..  ...              ...  ...
58   13           behind    3
59   15  to the right of   11
60   15  to the right of    9
61   15  to the right of    8
62   15  to the right of    2

[63 rows x 3 columns]