There is a good reason
I queried this piece of news with the tram forum on yahoo.co.uk, and I got an answer:
quote
There is a trend nowadays on many new tramway systems to have sections that are not powered through overhead wire. I don't agree with the spurious "aesthetic" argument for it, but we can't argue with the idiosyncrasies of local politics.
So the tram industry has been developing alternative power sources, including third rail, batteries, supercapacitors and fuel cells. I think economics will ultimately determine which method comes out on top, but it looks rather as though batteries are well up on the race at the moment, having benefited from many years' use in trolleybuses and pushed along by simultaneous development in the automotive and other industries. Whether the fuel cell will be economic or not remains to be seen.
unquote
ah well..
regards
Yoram