You can get your station from here:
http://transport.opendata.ch/v1/locations?query=koeln hbf
Just modify the url and it will give you this:
{“stations”:[{“id”:“008015458”,“name”:“K\u00f6ln Hbf”,“score”:101,“coordinate”:{“type”:“WGS84”,“x”:50.943029,“y”:6.95873},“distance”:null}]}
There you get the station id, in this case it’s 008015458