Where is the black smoke coming from?
The smoke is coming from the train.
    src        edge_attr  dst
0     0  to the right of   12
1     1  to the right of   12
2     1   to the left of    5
3     1   to the left of    9
4     1   to the left of   10
5     1   to the left of    8
6     2  to the right of    3
7     2               on    6
8     2  to the right of   11
9     2  to the right of    7
10    3   to the left of    7
11    3               on    6
12    3   to the left of    2
13    3   to the left of   13
14    3   to the left of   11
15    4   to the left of    9
16    5  to the right of    1
17    7  to the right of    3
18    7   to the left of    2
19    7               on    6
20    7           beside    0
21    8  to the right of    9
22    8  to the right of   10
23    8  to the right of    1
24    9   to the left of   10
25    9   to the left of    8
26    9  to the right of    1
27    9  to the right of    4
28   10  to the right of    9
29   10   to the left of    8
30   10  to the right of    1
31   11  to the right of    3
32   11   to the left of    2
33   12   to the left of    0
34   12   to the left of    1
35   13  to the right of    3
36   13      coming from    0
37   14           beside    0