I'm a big fan of narrow gauge train in Lego, but I always wrote off 4 wide track with minifig scale as too hard. However the Melbourne Lego Train Club didn't think so and have built a considerable layout including points/switches and a turntable!
(Photos Ross Crawford)
I don't really know much more than you can see the photos and this video, also by Ross Crawford, of the layout at the AMRA train show in Caulfield. If anyone has any more details about the layout, trains and builders, please get in touch.Edit: Some more search reveals that some or all of the models were built by Flickr user Alexander who has plenty more photos of the rolling stock.