Preloading AR doesn't work when no ActionDispatch is available since AR::SessionStore inherits from ActionDispatch::Something.
So I needed ActiveSupport::Autoload.autoloads to remove SessionStore from preloading.
I discovered that autoloads is a instance method and is used nowhere, so I guess this was overlooked.
@MSch what do you mean by "preloading"? Can you show an example of what you're trying to do?
I'm closing this as stale. Please let us know if you still have any issues with this, or want to add some example or real case, and we'll gladly reopen. Thanks!