Which kind of vehicle is in front of the hill?
The vehicle is a train car.
    src        edge_attr  dst
0     0  to the right of    1
1     1           behind    8
2     1   to the left of    7
3     1   to the left of    6
4     1   to the left of    8
5     1   to the left of    0
6     1   to the left of    5
7     2   to the left of   11
8     2           behind    5
9     4               on    3
10    5  to the right of    1
11    5      in front of    2
12    6  to the right of    1
13    7  to the right of    1
14    7               on    6
15    8  to the right of    1
16    8      in front of    1
17   10   to the left of   11
18   11  to the right of   10
19   11  to the right of    2