The line was still intact when I first went poking around there in 1974 or so, including a swing bridge across the Smith Canal (I think near the park where the SP 0-6-0 used to be), but I don't remember seeing any cars on the line. When I hired out on the WP in 1979, the mainline switch had already been removed. IIRC, the Switchman's Agreement (rather antiquated) that they gave me listed the North Channel line as one of the yard assignments that could be run with a foreman and just one helper instead of two (I believe the others were Winnemucca and Wendover, neither of which had yard jobs by that point), which suggested that traffic had been minimal for a long time.