What is the framework "escape hatch" for a SAFe ART that is running down the wrong track?

Question

Handling Incipient Failures in SAFe

In Scrum, there is the notion of Cancelling a Sprint and returning to Sprint Planning if the Sprint Goal becomes obsolete, or if the iteration plan is so far off base that scope can't be renegotiated without obviating the current Sprint Goal. However, I can find no parallel mechanism in SAFe 4.x that provides a similar escape hatch.

Given a Program Increment (PI) with goals that teams discover can't be met during the course of the PI, or Sprints/iterations within a PI that need to be replanned (not just re-scoped), what is the framework mechanism for doing so? While you're allowed to renegotiate scope in SAFe, sometimes that isn't enough to actually meet a goal; sometimes objectives or plans need to change, too!

Obviously teams can replan at iteration boundaries within a PI. There are also opportunities to introspect issues and improve planning in the future during the Inspect and Adapt (I&A) or Innovation and Planning (IP) cycles in SAFe. However, the notion that the Agile Release Train (ART) just keeps chugging along, even once it's discovered that the train is headed full-steam down the wrong track, seems fundamentally wrong to me. What have I missed or misunderstood about this aspect of the framework?

Answer 1

In my opinion these frameworks (SAFe, LESS, etc.) are very young and sometimes still half-baked. So until now teams have to figure out ways of how to handle unusual situations.
But you shouldn't miss the crucial point through all that smoke of uncertainty: it's about being agile. Literally. And yes, it's helpful to have a solid step-by-step guide when struggling with the more complex parts of daily project management (I'm looking at you, PMBOK), but agile projects are usually located in the outer regions of the Stacey matrix. So to me when being in these situations it's more about following the Agile Principles than following some rule book (and by the way, a rule book that's providing for all contingencies when sailing in unknown waters would be quite heavy).
So: if your team votes for an abnormal termination and if nothing speaks against it, abnormal termination it shall be.
Reverse the ART, reset the course and there it goes again full-steam.