Do you see either any trains or cars in the picture?
No, there are no cars or trains.
    src        edge_attr  dst
0     0   to the left of    6
1     0   to the left of    4
2     1               by    2
3     1   to the left of    2
4     1   to the left of    5
5     1  to the right of    4
6     2  to the right of    1
7     2  to the right of    3
8     3   to the left of    2
9     3   to the left of    5
10    3  to the right of    6
11    4   to the left of    1
12    4  to the right of    0
13    5  to the right of    3
14    5  to the right of    1
15    6  to the right of    0
16    6   to the left of    3