Which kind of vehicle is black?
The vehicle is a locomotive.
    src        edge_attr  dst
0     0  to the right of    4
1     4  to the right of    8
2     4   to the left of    6
3     4  to the right of    5
4     4   to the left of    0
5     5   to the left of   10
6     5   to the left of    7
7     5   to the left of    4
8     6  to the right of    4
9     7  to the right of    5
10    8   to the left of    4
11    8   to the left of   11
12   10  to the right of    5
13   11  to the right of    8