I'd had nearly forgotten about this thread, but Beeps and myself recently developed an automatic transportation system. I doubt any of you would like to redo the train stations considering how much work you've all put into them, but I think a lot of you would like the appeal of this design. Perhaps we can save this in our back pocket for when SG7 swings around?
Note, the current state you see it in is only a prototype. A proof of concept, if you will. Basically how it works is you place a chestcart and fill it with certain items. When you launch your minecart to go to the next station your chest minecart will travel in front of you. When you arrive at the next station a hopper will pull out a single item from the chestcart, and depending on what item that is, it will switch the tracks ahead of you in the station to redirect you to either a different station, or to make you stop. This would allow players to set and forget their routes, so they wouldn't have to get off at every single station then get back on.
To help explain I will use an example, look at the pictures in the album to get a better visual of what I'm saying.
Say you're at the southern station and you want to go to the north eastern station. That would take you 3 hops to get all the way there (South to Central, Central to North, North to North East). Now with this train station you wouldn't have to stop at every station along the way. You would place your chestcart and put in two diamonds and an iron ingot, diamonds would be in the first slot, iron ingot in the second slot. When you're ready to go, you press the button and you and your chestcart ship off. The chestcart will pass over a hopper in front of you and have a diamond taken out of the cart. The station then thinks 'Oh, I got a diamond, this must mean this person wants to go north!' and the station will redirect you to the northern line which will lead you to central station. This will repeat at central station. Once you're at the northern station the station will take out the iron ingot of the chestcart and think 'Ah, this person wants to go east now.' and it will redirect you in the eastern direction towards your final destination of the north eastern station.
TL;DR You pre-program a route using items inside of chestcarts that will allow you to AFK an entire trip.
Also, a lot of objections to this design have already been considered. We are using 5 out of the 6 pieces of possible data we could give the stations. The 5 pieces of data are NORTH, SOUTH, EAST, WEST, and STOP. Each direction can be represented by any item, however we have STOP represented as a lack of items. Hoppers have 5 inventory slots, so we could potentially filter a fifth item, but we don't have any use for that as of now. However, the last piece of data could be used for shipping chestcarts full of items between stations, but this would require a large redesign of the current machine.
All incoming traffic would be filtered through the same line, so we wouldn't have to duplicate this machine 4 times.
We don't have a cart collection system setup, we're a bit undecided on that. In my opinion I would recommend that everyone carried a single minecart and chestcart in their Enderchest, but there's other options to this.