It's also worth mentioning that I already have a planned connection to Sandwich's place, my rail runs right next to it underground. I will be completing that one after this one is done.
Cool! I haven't done much work on my place ever since being given creative for building the Fenris; I want my place to be mostly legit.

Anyway, since you say it runs underground, see about connecting it to the walkway I have spiraling down the circumference of The Pit - I don't mind if people enter the place from there. I consider that entire domed pit area a public area; I'll be making all sorts of underground rooms (and perhaps above-ground structures) for the private areas.
Strange idea that literally came to my mind 10 seconds or so ago. We could colour the line of blocks where rails are on, with different colours (red brick, black obsidian, grey cobble, yellow sandstone, blue dia-.. well maybe not diamond) to seperate the rail-lines from eachother.
*snip*
Funnily enough, I had the same thought reading the posts above yours, and then I came across your post.

However, I was thinking of using colored wool blocks for marking the rail lines; it would give us decent coloring for both the map and in-game, plenty of different lines to color, etc. The only problem is flammability, but I don't see that ever really happening.
We should leave changing track blocks with wool up to those bestowed with WorldEdit powers, though, since they should be able to switch the cobblestone with wool right under the rails, without them popping off.
If people dislike the idea of having entire rails out of wool, we could perhaps just have those side blocks that have torches on them be colored wool; hopefully they'd be regular enough to make the color of any given rail discernible on the map.
My main point here is though, that using signs a cart can have a "tag" added to it, and that "tag" can be read at a track switch to determine which way it goes.
This means that multiple lines can use the same section of rail, but be switched in an other direction if it has the appropriate tag.
This gives me an idea. that you WorldEditors would have to implement:
- Generate concentric, octagonal double-rail rings every 500-100 meters, centered around spawn. Make each ring Place them pretty high up, perhaps at around y:120 or so, so that they'll be less likely to intersect with an already existing structure. All us players would have to agree that If they do intersect, we'd take it upon ourselves to implement a workaround, be it routing that segment of rail around or through the structure in question, or perhaps even implementing a station if feasible.
- Generate double-rail spokes every 45 degrees, a few blocks higher or lower than the octagonal rings. We'll build simple transfer stations at every intersection. A water drop and ladder elevator can facilitate access from the ground to each transfer station. Where appropriate (such as in high mountainous terrain), these can be replaced with a stairway or bridge from the nearest mountain peak. Alternately, have the spokes at the same level as the rings, and use the TrainCart tags to manage intersection behavior.
- At (or near) ground level below each intersection (or at the end of the access bridge or stairway), we could have a simple structure to act as a hub for secondary rail lines. Players would be responsible for building these secondary lines from these ground-level hubs to their houses or wherever.
This way we'd be able to have easily-navigable rail lines running across the entire map, providing easy access to any area, without placing a huge resource burden on the outlying settlements.
Whatcha'll think?