The Renaissance of Trolley Buses
While I applaud the advocacy for light rail by The Greens, the greatest impediment to adoption will be the start up cost. This consists of the three major infrastructure expenses: construction of electrical power lines (overhead or third rail arrangements), installation of rails, purchase of rolling stock.
An alternative approach which works well are electric trolley buses. These are basically stock buses, but with electric motors and overhead electric busbars to pick up the electricity in the same way as trams. In comparison to the early systems in use in Australia and elsewhere, there are now the technologies to run in dual-mode, on and off the electric wires.
While the first infrastructure cost of electric power lines still has to be met, rails and expensive trams need not be. The existing buses could actually be converted, without requiring their replacement. Existing bus drivers need only minor additions to their training. Trolley buses are part of the existing motorways and do not require changes to signalling. Since only powerlines need to be provided, this reduces the cost to implement these beyond the central business districts and downtown areas which is necessary for Australian cities.
These are systems which are already in operation in cities such as Seattle, and the advocates for light rail should strongly consider trolley buses as a graduated, low cost entry into provision of light rail.