What's the train on?
The train is on the train tracks.
   src        edge_attr  dst
0    0            above    7
1    1   to the left of    7
2    1   to the left of    8
3    3               on    7
4    5   to the left of    9
5    7  to the right of    1
6    8  to the right of    1
7    9  to the right of    5