What vehicle is behind the numbers that look white?
The vehicle is a train.
    src        edge_attr  dst
0     0  to the right of    4
1     0  to the right of    7
2     0  to the right of    6
3     1   to the left of    7
4     2   to the left of    7
5     3           around    4
6     4        on top of    3
7     4         crossing    3
8     4           behind    6
9     4   to the left of    0
10    4          exiting    3
11    5  to the right of    7
12    6      in front of    4
13    6  to the right of    7
14    6   to the left of    0
15    7   to the left of    6
16    7  to the right of    1
17    7   to the left of    5
18    7   to the left of    0
19    7  to the right of    2