UP 2900 is mated up with another U30C at Argo Yard under the yard tower and freight offices. UP was dominated by EMD power at this time, but U28Cs, U30Cs and U50Cs would show up on occasion. As the EMD GP38-2s and SD40-2s began arriving, the era of UP experimentation with high horsepower waned, and soon GE would gain marketshare with their C30-7 loco.