By the early 1980s, the Rio Grande Zephyr was losing money. To reduce costs, the D&RGW was looking for ways to economize. By the summer of 1982, they tested alternative power arrangements to reduce fuel consumption. One GP40-2 and one F9B were tested with mixed results. Two GP40-2s, No. 3116 and 3119 were evaluated on July 15-16th with no F9s at all. Apparently, this one time experiment didn't perform well either. By October, the trio of F9s were back on the beloved streamliner.
