Are there either any trucks or trains that are not gray?
No, there is a truck but it is gray.
    src        edge_attr  dst
0     2   to the left of   16
1     2   to the left of    6
2     2  to the right of    5
3     2   to the left of   13
4     2   to the left of    7
5     5   to the left of    2
6     5   to the left of   13
7     5   to the left of    7
8     5   to the left of   16
9     6   to the left of    9
10    6   to the left of    8
11    6  to the right of   13
12    6   to the left of   12
13    6  to the right of   16
14    6   to the left of   14
15    6  to the right of    2
16    7   to the left of    8
17    7  to the right of    5
18    7  to the right of    2
19    7   to the left of   12
20    7   to the left of   14
21    8  to the right of   16
22    8  to the right of    6
23    8  to the right of    7
24    8   to the left of    9
25    8   to the left of   12
26    8  to the right of   13
27    8  to the right of   14
28    8       sitting on    4
29    9  to the right of   14
30    9  to the right of   12
31    9  to the right of    8
32    9       sitting on    4
33    9  to the right of    6
34   12  to the right of   14
35   12   to the left of    9
36   12  to the right of    8
37   12  to the right of    7
38   12  to the right of    6
39   13   to the left of    8
40   13   to the left of   14
41   13  to the right of    2
42   13   to the left of    6
43   13  to the right of    5
44   14   to the left of    8
45   14   to the left of    9
46   14  to the right of    6
47   14  to the right of    7
48   14   to the left of   12
49   14  to the right of   13
50   14  to the right of   16
51   16   to the left of   14
52   16   to the left of    8
53   16  to the right of    2
54   16   to the left of    6
55   16  to the right of    5
56   18   to the left of   22
57   22  to the right of   18