2.3 Two-Rail Position
When the tangent line points the wrong way
When the cue ball needs to detour
Sometimes the spot where you need the cue ball is on the opposite side of the tangent line. Going there directly is impossible.
Solution: two-rail position. Hit the shot harder, let the cue ball bounce off two cushions, end up where you want.
Skill required: predict cushion rebounds. Combine the 90° tangent rule with incident=reflection on each cushion.
Bounce paths = chained mirrors
The cue ball's path off N cushions equals a straight line on the unfolded mirror table. To trace it manually:
- From the impact point, draw the 90° tangent line (or 30° rolling line) — that's the start direction
- Continue until it hits cushion #1 → reflect (incident = rebound)
- Continue until cushion #2 → reflect again
- ...until the cue ball runs out of energy
Power decides how far the chain goes — how many cushions it takes before stopping.
- Path = tangent direction + chained reflections
- Each rebound roughly equal to incident (stun only — running roll bounces steeper, sidespin warps it)
- Power = how many cushions the chain reaches
Decision flow upgrade
From Lesson 2.2: pick cut + pick power.
Two-rail upgrade:
- What zone do I need the cue ball to reach?
- Trace the tangent — does one cushion get me there?
- If not, does two?
- Tune power to land in the zone
Most common beginner failure: power too low, cue ball stops on its first tangent run instead of reaching the bounce path. Two-rail position needs 65%+ power.
Drills below — hit hard, plan the bounce.