What is the vehicle that is on?
The vehicle is a train.
    src        edge_attr  dst
0     0  to the right of    1
1     1   to the left of    2
2     1   to the left of    0
3     2  to the right of    1
4     3               on    9
5     3  to the right of    6
6     4  to the right of    6
7     4  to the right of    5
8     4  to the right of    8
9     5   to the left of    4
10    5  to the right of    6
11    6   to the left of    4
12    6   to the left of    5
13    6  to the right of   13
14    6   to the left of    8
15    6   to the left of   11
16    6   to the left of    3
17    6   to the left of   10
18    7   to the left of   11
19    8   to the left of    4
20    8   to the left of   10
21    8  to the right of    6
22    9               at   12
23   10  to the right of    8
24   10  to the right of    6
25   11  to the right of    7
26   11  to the right of    6
27   13   to the left of    6