Shown above is our version #1 model of a Union Pacific Challenger. This early service coal-fired example varied only slightly from the original as-built configuration. There were three production orders each had it's own unique details and those have been represented on each of our models based on road numbers appropriate for each production order. The model above is road number 3930 which makes it a class 4664-5 locomotive which was the designation for the last production order, the final group of locomotives built.