What is the train on?
The train is on the bridge.
     src        edge_attr  dst
0      0   to the left of   23
1      0  to the right of   24
2      0   to the left of   16
3      0   to the left of   15
4      0   to the left of   22
..   ...              ...  ...
132   25  to the right of   16
133   25   to the left of    4
134   26  to the right of    8
135   26   to the left of   12
136   26  to the right of    9

[137 rows x 3 columns]