What is the meaning of the following traffic sign?

1. A distance of about 250 meters to an approaching level crossing.
2. It is prohibited to stop within a distance of 120 meters before the railway tracks.
3. A distance of about 70 meters to an approaching level crossing.
4. Correct answer: Approach to a level crossing. Approx 200metres before the crossing

WhyTwo stripes on the board mean about 200 m to the crossing. Three stripes mean 300 m, one means 100 m.