Well, quite frankly the only detail thus far is this:
It's been a while since Twilight turned alicorn, and research and development have skyrocketed. No longer are train tickets needed because trains were replaced by teleportation stations that lead to various set destinations, and androids are present in the homes of many ponies (kinda the same deal with a story I have called "Manufacturer's Label").
The Elements of Harmony are the one thing that can protect Equestria, but they've gotten ahead in years, and really can't keep vigilant, so a set of six surrogate droids are made to take up the positions of the current EoH. Of course, this isn't perfect, but it's proven effective thus far considering how often these surrogates need maintenance.