Which kind of vehicle is it?
The vehicle is a train.
   src        edge_attr  dst
0    0          wearing    3
1    0      waiting for    1
2    0          wearing    2
3    0          holding    5
4    0          wearing    6
5    3   to the left of    5
6    4   to the left of    5
7    5  to the right of    4
8    5  to the right of    3