There is still one thing confuses me, there are many underground platforms and Perth
train station platforms, when i observe the data and the map, i found stop id 99601
and 99602, which locate in the center of the map, they are both underground station,
in the same location, just different platform number.
so the underground station or Perth train station not only limit to id 99007 and
99601,(because only 99007 and 99601 mentioned in task 3, i thought only these two id
are underground station or Perth train station).