When must you wait at this traffic sign?

The sign displayed is a warning sign indicating that you are approaching a railway crossing. In Germany, when this sign is visible, specific actions are required to ensure safety.

1. **When a railway employee is waving a white-red-white flag**: This indicates that it's not safe to cross and you must stop until you receive further instructions.

2. **When the level crossing cannot be crossed without having to stop on it**: If you cannot clear the crossing without stopping, you should not enter the crossing area to avoid potential accidents with a train.

3. **When a rail vehicle is approaching**: If you see or hear a train approaching, it is crucial to stop, as trains cannot stop quickly.

Understanding and adhering to all these points is essential for your safety and to comply with German traffic laws. This combination ensures that you are aware of all necessary safety precautions when dealing with railway crossings.