What vehicle is on the bridge?
The vehicle is a train.
    src        edge_attr  dst
0     3  to the right of    4
1     3   to the left of   10
2     3          next to    9
3     3             near    9
4     4   to the left of    7
5     4   to the left of    8
6     4   to the left of    3
7     5   to the left of   10
8     6   to the left of   10
9     7          driving    9
10    7  to the right of    4
11    7          wearing    5
12    7  to the right of    8
13    7   to the left of   10
14    8  to the right of    4
15    8   to the left of    7
16    9               on    0
17    9             near    3
18   10  to the right of    7
19   10  to the right of    6
20   10  to the right of    5
21   10  to the right of    3