Stables were the crowning achievement of Stable-Tec. Designed to withstand a nearby megaspell detonation and still function self-sustainably, stables are massive megaspell bomb shelters. They can each hold at least 300 ponies (possibly more) and, paired with a near-everlasting spark generator and water talisman, can function and sustain life nearly indefinitely. Stables were equipped with sensors that could determine levels of toxicity in the air and soil above them, necessary to determine whether it would be safe to open the otherwise constantly sealed door that led outside.
- Main article: List of Stables
Some stables were designed to mimic and simply preserve life before the war, while many were not. Many stables were modified in the design stage to accommodate different social experiments in an attempt to develop a community or culture less likely to repeat the mistakes of the past. Only Apple Bloom, Scootaloo, and Sweetie Belle knew that these social experiments were in place beforehand.
The various stable designs were for the most part successful, with the only noted failures occurring due to accidents within. As stables were designed to be self sustaining and isolated, an irreparable problem such as a faulty or damaged piece of life supporting equipment would usually be unavoidably fatal to the entire stable.
The only significant failure of a Stable was that of Stable 3 near Canterlot. While able to repel the explosion and radioactive fallout of a megaspell detonation, the magically corrosive Pink Cloud slowly ate into and eventually breached the stable over a century -- its residents attempted to flee; some succeeded, others were killed, and still others became ghouls.
Project Horizons Stable Designs
In chapter 19 of the non-canon Project Horizons, the main protagonist Blackjack discovers various radical Stable concepts splayed on Terminals within Apple Blooms' Office in the Hoofington region, many of them considered a step-away from the traditional underground Stables. Some built to be underwater, built as oceanic islands, built to be above the cloudline, built as pyramids, and even Stables built in orbit around the planet. It is unknown if these Stables were merely conceptual designs or were actually implemented and completed before the Last Day.
|“||You have a serious problem here. Have you even looked at the population reports? Do you have any idea how many of the original inhabitants of this Stable were extended members of the Apple family? By Celestia, even Littlepip and I have a common Apple ancestor six generations back! [...] This entire Stable is in danger of a becoming completely inbred,||”|
If a Stable plans on sustaining itself forever a pair of ponies always has to have two foals, one filly and one colt. To make the calculation easy we group a pair of siblings. For the Stable to survive a whole generation there has to be an additional pair of siblings, at least four ponies total. For a second generation, there has to be another two pairs of siblings, making eight ponies in total, and so on and so forth. With three generations alive at the same time and a new generation born every 25 years it is easily calculable how many ponies need to be in the Stable for it to be inbred-free sustainable.
|Ponies per Generation||4||8||16||32||64||128||256||512||1024||2048|
|Years inbreeding is avoidable||25||50||75||100||125||150||175||200||225||250|
|Total amount of Ponies in Stable||12||24||48||96||192||384||768||1536||3072||6144|
As Stable-Tec never knew just how long Equestria would remain uninhabitable, and they had to work commercially, so they weren't able to just up the total amount of ponies to fit in a Stable. A compromise has been found at a population of about 300 ponies where only after five generations (or 125 years) everypony in the Stable will be related to one another.
Behind the Scenes
Stables are based off Vaults from the Fallout games.