Okay. Well, like I said, I harm brain cells when I try to make BLB files.
I need 6x wide versions of all of these:

I also need a new minecart vehicle that fits over a 6x railway. Nothing too complex - it's only a bot with a seat. Something like:

but without the contents?
I don't see why we can't keep 4x rails on the side though. We could have two types of train.
EDIT:
Some more detail on the current brick sizes + what the new ones have to be:
Straight Rail Guide - 4x8 -> 6x8
Sharp Corner - 4x4 -> 6x6 (This doesn't have an actual brick in the current mod version so feel free to leave it out btw)
Corner - 2x4 -> 2x6 (Same as corner)
Filler Guide - 1x1 -> N/A (Don't worry about this one at all, it'll work just fine whatever)
Booster - 4x8 -> 6x8
Intersection - 6x6 -> 8x8 (When you convert this one, can you possibly replace the circle with something more... intersectiony? A plus sign, or whatever.)
LauncherTrain Interaction Brick - 6x6 -> 8x8 (Been working on this, I can probably get away with porting the Warp Gate brick over for it)