What vehicle is in front of the apartment building?
The vehicle is a train.
    src        edge_attr  dst
0     1   to the left of   15
1     1   to the left of   19
2     2   to the left of   14
3     2  to the right of   15
4     3  to the right of   16
5     3  to the right of    4
6     4  to the right of   16
7     4   to the left of    3
8     5   to the left of   10
9     6   to the left of   10
10    6      in front of   19
11    6   to the left of   18
12    7   to the left of   19
13    7   to the left of   12
14   10  to the right of    5
15   10  to the right of    6
16   11  to the right of   12
17   11   to the left of   18
18   12  to the right of   13
19   12  to the right of   16
20   12   to the left of   11
21   12  to the right of    7
22   13   to the left of   19
23   13   to the left of   12
24   14  to the right of   15
25   14  to the right of    2
26   15   to the left of    2
27   15  to the right of    1
28   15   to the left of   14
29   16   to the left of    4
30   16   to the left of    3
31   16   to the left of   12
32   17      in front of   19
33   17           beside    6
34   17               by    6
35   18  to the right of   11
36   18  to the right of    6
37   19  to the right of    1
38   19  to the right of    7
39   19  to the right of   13
40   19           behind   17
41   19           behind    6