lawn

I found something bizarre at a station. A plate of lawn on the rail track. The green grass is growing on the plate on the track. Strangely, only a small part of the track is covered and the track on the other side is not covered.

I asked a station attendant about this weird green carpet. ''It has been there for some time now", he told me. But he did not know who installed it or for what. Actually, he was wondering too. Do you have any idea?