Final answer:
A six car R46 train operator should stop at the sixth dot marker, which aligns with the Car Y marker for proper station alignment.
Step-by-step explanation:
A train operator operating a six car R46 would stop his/her train in the station at the sixth dot marker. This position corresponds with the Car Y marker, which is described as being one and two third perpendicular hash marks to the left of the center bottom hash mark. It is crucial for operators to stop at the correct marker to ensure the safety and proper alignment of the train at the station platform.