Does the train have a different color than the house?
Yes, the train is black and the house is white.
   src        edge_attr  dst
0    0  to the right of    2
1    2   to the left of    0
2    2  to the right of    4
3    4  to the right of    7
4    4  to the right of    6
5    4   to the left of    2
6    6  to the right of    7
7    6   to the left of    4
8    7   to the left of    6
9    7   to the left of    4