To the north and south, the city is quite sprawling but is limited to the east and west by the sea and hills. To the north it goes as far as Gawler before it starts thinning out and to the south to Seaford. Housing continues beyond that to Aldinga and Sellicks but it thins out a bit. As you go south on a map, the gap between the sea and hills narrows and that is reflected in the width of the built up area down there. Currently, the train only goes as far as Noarlunga but it is being extended 5.7km down to Seaford. Most of it will be on a long bridge. You can see a time lapse of how it is going so far here:
The metropolitan area is also very flat. If you've been for a walk or drive in the hills, that's obvious for anyone to see.
Adelaide is ideally set out for a north to south railway with a network of bus routes and bike routes feeding into the stations. We have the railway. We have bus routes that don't always correspond to the railway. But the bike routes are yet to come.
The State Government announced not long ago that they were investing $2b into public transport in Adelaide. It included new trams and buses and a substantial infrastructure project that involved converting the metropolitan railway system to standard gauge, electrifying it and buying shiny new electric trains (the interiors are being done by a local company). It was brilliant. I think the decision to convert to standard gauge was to allow for further expansion into the future. As part of that spending, the old railcar depot near Adelaide central railway station was moved (to allow space for the new hospital) to a shiny new one at Dry Creek north of the city in preparation for the new trains. The new depot is complete is is used to service the current diesel trains.
In preparation for standardisation, a lot of the track north and south of the city has been resleepered and relaid to allow smoother running. The new sleepers are dual gauge so that when the time comes, the rail can be moved across with a minimum of fuss:
Having said that, converting all of the points (switches) will be a nightmare.
In the latest budget, because revenues have fallen, the announcement is that we're only going to get half of it for now. Electrification north of the city will be deferred (for how long we don't know) while the electrification south of the city will continue. A consequence is that we have to renegotiate the order of electric trains that has already been made.
If you ask me, our Treasurer hasn't really thought this through. Here's a map of the railway network:
The red line going north will not be electrified but the blue one going south will be. In other words, for an unspecified time, you will have electric trains south of the city and diesel trains north of the city. Not necessarily a problem you might think. Follow the red line up 6 stops from the city to Dry Creek and that is where the new depot is. It was suggested somewhere recently that the electric trains could be towed to the depot (by what is not clear). Thankfully, the new electric trains (how ever many we end up with) will be broad guage rather than standard as was announced back in 2008. When that decision was made is not entirely clear but it does seem certain that they will run on the tracks as they currently are. Had they not been, you can imagine trying to get electric standard gauge trains along a non-electrified track that is the wrong gauge so that they can be serviced!
In the meantime, we have a half electrified network for an indefinite period. As I say, I think it's a joke. A brilliant one. But a joke nonetheless.
NB: For non train tragics, the gauge is the distance between the two rails. There is a "standard" gauge used by 60% of the world's railways. Adelaide's metropolitan network uses a broad gauge. It is an accident of history caused when the various Australian colonies adopted different gauges before Federation. South Australia has used at least three different gauges at one time or another. The remnants of the narrow gauge network can be seen on the Pichi Richi Railway.