- Marty: "What does this mean, "Point of No Return"?"
- Doc: "That's our fail-safe point. Up until there, we still have enough time to stop the locomotive before it plunges into the ravine. But once we pass this windmill, it's the future or bust."
- — Marty and Doc discuss elements of his demonstration model in 1885, Wav
The Point of No Return was a windmill along Carson Spur that indicated that it was too late to turn slow down the train before it went off the edge of Shonash Ravine.