Bill,
Yes the overhead does appear to be for normal pantograph operation,
however what is different is that; double contact wire has been hung. I
am not sure of the reasoning for this maybe someone else can provide the
answer, it may have something to do with better pick up for the 750V dc
taction current. I have noted new overseas Light Rail systems also using
double contact wire as well. (Indeed the SRA uses this method for high
current demand sections such as coal lines)Aside from Melbourne which
has sucessfully combined panto and trolley pole operation, the sydney
system is exclusivly panto only.