There is a narrow gauge / standard gauge crossover near the South Freo power station, it is a left over from the old Robb's Jetty freight terminal days, it serves no purpose other than the narrow gauge and standard gauge swap sides. Due to this being an un-signalled crossover it makes the narrow gauge and standard gauge tracks to be operated as a single duel gauge track between South Beach and Cockburn.
Its a legacy of the days when the narrow gauge yard was on the east side of Robbs and the SG was on the west . For those unfamiliar with the history of the area, until 1986 the line between Cockburn and Freo consisted of two independent mains, one narrow and one standard. In 1985 the track between Freo and the North end of Robbs Jetty was converted to dual gauge, with the facing points for the yard just south of the then new south Beach platform. When Robbs was closed the yard was ripped up and rather than do the obvious and extend the dual gauge south all the way to the crossover, the mains were kept intact, resulting in the unusual arrangement that exists today. As far as I can tell, this diamond, being a different gauges diamond crossing is only one of a handful of such left in WA. The only other two that I can think of are at Merredin and Kwinana, the later being a beauty in that it is a dual gauge /standard gauge diamond- possibly now unique in Australia.
Perhaps one day we will see the sparks extended south of Fremantle, although I suspect that it will be a long time away. Certainly, the issues of managing the interface of railcars with real trains driven by real drivers ( or, shudder, maybe even real train controllers!) will be a source of both interest and amusement.