The station platform is not strictly required to be straight, it can be curve, but this will increase the risk that passengers trip over by the larger gap in some place(plenty examples around the world, including London and New York)
London's gaps are hilarious.
I totally agree with your words about choosing SD rolling stock rather than a DD one for metro. There are only limited rail systems over the world using DD stocks for commuter services, and most systems use SD and many rolling stock manufacturers produce tons of SD trains every year (Japan, China, Europe, everywhere!). They are more experienced on making SD trains. They have plenty well-developed SD train design / models for their client to choose from and can produce a lot of SD trains straight away. A vivid example is when China building the body for Waratah trains, they spent longer time to configure, test and reconfigure their machine to produce a fitted body for the new trains, and of course you can see, still have some problems. And when they were trying to build the body of the A set, they built couple SD metro stocks and delivered to Guangzhou, Middle East and somewhere else.
Yes and no. I'll call upon the analogy of the shoe and the foot. Logically, you would fit the shoe to the foot, amirite? That would mean taking a good look at the suburban railways in Sydney and getting them the train they need; fitting the foot to the shoe would be like looking at the trains on the shelves, picking one and shoehorning it into Sydney.
Just because SD stock is easily obtained doesn't mean it should be bought. To me, this reeks of some highly-placed "advisors" and their attraction to SD stock, trying to find an application for SD stock. I realise I'm cynical in saying that, and possibly also conservative in preferring the retention but reconfiguration of DD stock.
In my point, what passengers want is fast, reliable and comfortable rail service, they don’t care whether those services are operated by a DD stock or a SD stock. If you could give the NW 10-12tph, they still can have seats as trains coming frequently and if the platform is crowded and you really want a seat, simply wait the next train, it won’t take much time isn’t it?
Ya - that's the point. There has to be the frequency and the capacity. The passenger cares not whether the train has fluted sides or not; he cares for the train to show up quickly, have a decent seat for his bum and take him where he wants to go in a jiffy.
How about powering the train? You can convert it to third rail and you are free to worry about the vehicle height.orly.jpg
I do believe that there's still a height restriction due to the height of the tunnel. Also, I would not advocate the conversion or introduction of third rail in Sydney.
There are tons of solutions to make Sydney rail system better BUT the most important thing is the state government should TALK LESS and WORK MORE, and WORK NOW!! If you are out of budget, don't talk about it! I feel angrier when the government keep making promises to me than they just told me “we won’t do anything on the rail network this year”.
While I can certainly sympathise with your burning desire to see something actually built in our lifetime, I merely wish to point out that every project requires some degree of planning. In this case, I very much doubt that the physical infrastructure of the NWRL will change much; rather, what will run on those tracks has been changed.