What is the signal light on?
The signal light is on the pole.
    src        edge_attr  dst
0     0             near    9
1     0  to the right of    3
2     0             near   13
3     0      in front of   13
4     0  leaning against    9
..  ...              ...  ...
89   18   to the left of   12
90   18               on    6
91   19   to the left of   12
92   19  to the right of    9
93   19  to the right of    2

[94 rows x 3 columns]