I don’t know how common these things are outside of Switzerland, but at least in Switzerland they are becoming more and more common.
This is it – a weed shocker:
I think their official name is steam weeding machine. Sadly, I don’t know what these machines are called in German, but it wouldn’t surprise me if it was something along the lines of Dampfunkrautvernichtungsanlage or Dampfunkrautbereinigungsmaschine.
The idea is to kill weeds dead by blasting them with extremely high temperature steam, rather than by the use of chemicals. Presently, the Swiss Federal Railways use a carcinogenic weed killer to keep their rails clean and free of weeds – they plan to convert to 100% weed shockers in the next few years.