This paper considers target tracking problems where the range measurements are partially interrupted. A multiple model tracking filter is developed for this problem. By using a soft switching mechanism, the proposed filter automatically abandons the erroneous range measurements in the interrupted time intervals, and captures the remaining correct range measurements for tracking estimation. It has a simplified structure compared to the IMM filter and offers simplicity in the design. A numerical example demonstrates that the filter can maintain an effective tracking in random range measurements interruptions as well as in deterministic cases