Funny.... I have seen something similar in Riga. Sometimes there are single
tracks (connected to either one or both of the tram tracks) going towards a
large gate - probably not passenger traffic.
I have only once seen a tanker-tram there, I am not sure how much fright
they have.
But it looks to me, that the tram network is connected to the rail network
(which is funny since trains run on 1520mm, trams on 1524 AFAIK).
Well, seems like this is in use other places in the world. What is the tram
system gauge there?
Here's some photos of the new freight service on Vienna's tram lines. They're aparently named "bims" because of the sound of their warning bell: (6 URLs) Link to original page in German> (20 years ago, 23-May-05, to lugnet.trains, FTX)