"Batman55" wrote

Surely the white lights which show horizontal (stop), vertical (go) and
diagonal (junction) count as signals? The drivers certainly treat them
like
signals!

Indeed they are. Tram drivers are not required to observe road
(red/amber/green) traffic lights, but there will be a white dot signal head
at the same location. These are also to be found at junctions, level
crossings, and at the section of interlaced track. Elsewhere the trams are
driven on sight.

Peter