: Independently rotating wheelsets (IRWs) are increasingly adopted in low-floor urban rail vehicles because they enable compact bogie layouts and improved curving performance. However, their limited natural self-centering capability can lead to lateral offset from the track centerline, increased flange contact, and degraded lateral guidance performance. This paper presents an LQ-servo-based differential-torque control method for active centering of IRWs using a control-oriented state-space model derived from linearized wheel–rail creep-force relations. The left and right wheel torques are employed as actuation inputs to regulate the lateral displacement of the wheelset, while a conventional proportional–integral–derivative (PID) controller is implemented as a baseline for comparison. The proposed method is evaluated through numerical simulations and validated experimentally using a 1/5-scale IRW roller rig. The results demonstrate that the LQ-servo-based differential-torque controller achieves faster centering, improved yaw damping, reduced steady-state lateral offset, and feasible control effort compared with the PID controller. These findings support the effectiveness of the proposed modeling and control approach for active centering of independently rotating wheelsets.