This is an additional sign Austria is attaching to 3,500 level crossings that have no protection other than a cross sign (Andreaskreuz – saltire), a stop sign and the whistle of the train. It tells them to listen out for the whistle. It’s not clear whether the sign can be understood by kangaroos.
The Highway Code on various types of level crossings.
bq. Open crossings
271: These have no gates, barriers, attendant or traffic lights but will have a ‘Give Way’ sign. You should look both ways, listen and make sure there is no train coming before you cross.