What is the train on?
The train is on the platform.
    src        edge_attr  dst
0     0               on    1
1     1  to the right of    6
2     2  to the right of    6
3     3               on   11
4     5  to the right of   11
5     6   to the left of    2
6     6   to the left of    1
7     6   to the left of   13
8     6               on    7
9     8  to the right of    9
10    8   to the left of   10
11    8  to the right of   12
12    8   to the left of   15
13    8   to the left of   16
14    9   to the left of    8
15    9  to the right of   12
16   10  to the right of    8
17   10  to the right of   16
18   10  to the right of   15
19   11   to the left of    5
20   12   to the left of    8
21   12   to the left of    9
22   13  to the right of    6
23   13               by    6
24   15               at   10
25   15  to the right of   16
26   15               at    4
27   15   to the left of   10
28   15  to the right of    8
29   16               on    7
30   16   to the left of   10
31   16   to the left of   15
32   16  to the right of    8