| UP 3999 was a one-of-a-kind experiment with the road rebuilding one of its SD24s with a 16-645 prime mover at 3000HP- very simliar to an SD40. Originally delivered as UP 423, it would subsequently be numbered 3100, 3200, 3399, 3999 and finally 99 before being sold for scrap in 11/85. The multiple renumberings were required as waves of EMD SD40s and 40-2s forced a change. It's shown here in consist on a gray January day. For more details see Don Strack's exceptional "Utah Rails" site. |