KanjiJLPT N1
Track

rut, wheel, track, model, way of doing

Mnemonic

A car completes nine laps around the same track, each pass carving the grooves deeper into the earth. By the ninth lap, the ruts are so deep the car can't steer away—it's locked into the track forever, forced to follow the path nine rounds of wheels have worn.
Additional thoughts
Picture a race car going around nine times, each lap etching ruts so deep they become permanent rails. Nine repetitions = an established, inescapable course.
Quick recall
A car doing nine laps carves a permanent track into the ground.

Details

The keyword for 軌 is track. This kanji refers to the ruts or grooves left by wheels, and by extension, a rail or track along which vehicles travel. It also carries the broader metaphorical meaning of a path, course, or established way of doing things, as in staying "on track." The character conveys the idea of a fixed route or trajectory that guides movement or conduct.
On'yomi