My understanding is that the rails were removed in 1942. I could have been a process that lasted in '43. Several railfans made a "last-trip" prior to entering war-time service in the winter/spring of '42 and took photos showing the rails in place. In last-year's book by Joe Dale Morris (published by SPH&TS) there is a photo of a train of salvaged ties at Benton, California.
Just today at Nevada Historical Society, I was looking at a profile of the line that the SP surveyed and drew up in 1906 and made some notes. The curve on this fill is a 20° curve, the fill is about 18' high and at that point the grade is 1.37%.
The grade over Montgomery had a max of about 2.5%, but the steepest was between Tonopah Jct. and Belleville where through the canyon it was 2.6%.
Brian Norden