How is the vehicle that the ladder is on called?
The vehicle is a train.
    src        edge_attr  dst
0     0   to the left of   18
1     2             near   18
2     2               on   15
3     2   to the left of   10
4     2   to the left of    4
5     2   to the left of   18
6     3   to the left of   16
7     4  to the right of    2
8     7  to the right of    9
9     7  to the right of    8
10    8   to the left of    7
11    9   to the left of    7
12   10  to the right of   17
13   10  to the right of   13
14   10  to the right of    2
15   13   to the left of   18
16   13   to the left of   10
17   13               on    2
18   16   to the left of   17
19   16  to the right of    3
20   17       working on    2
21   17  to the right of   16
22   17   to the left of   10
23   17   to the left of   18
24   18  to the right of   17
25   18             near    2
26   18  to the right of    2
27   18  to the right of    0
28   18  to the right of   13
29   18          wearing   10