What color is the vehicle the sign is on?
The train is green.
    src        edge_attr  dst
0     0   to the left of    6
1     0   to the left of    9
2     0  to the right of    8
3     0   to the left of    1
4     0  to the right of    5
5     0  to the right of    3
6     0  to the right of   11
7     0  to the right of   10
8     1  to the right of    0
9     1  to the right of    7
10    1  to the right of    9
11    2  to the right of   10
12    2   to the left of    6
13    2  to the right of    4
14    2  on the front of    0
15    3   to the left of    0
16    3   to the left of    5
17    3   to the left of   11
18    4               on    0
19    4   to the left of    2
20    4   to the left of    6
21    4  to the right of   10
22    5   to the left of    0
23    5  to the right of    3
24    5  to the right of    8
25    6  to the right of    4
26    6  to the right of    2
27    6  to the right of    0
28    6  to the right of    7
29    6  to the right of   10
30    7  to the right of   10
31    7   to the left of    6
32    7   to the left of    1
33    8   to the left of    0
34    8   to the left of   11
35    8   to the left of    5
36    9  to the right of    0
37    9   to the left of    1
38   10   to the left of    6
39   10   to the left of    7
40   10   to the left of    2
41   10   to the left of    4
42   10   to the left of    0
43   11  to the right of    3
44   11   to the left of    0
45   11  to the right of    8