In 1958 UP contracted with EMD to rebuild / upgrade F3 units with F9 mechanical components utilizing anything serviceable from the F3s. In February 1972, the UP Fâs were destined for trade-in but a deal was struck with power-short CRIP (Rock Island) and their F units were substituted in exchange for the UP Fs. CRIP immediately pressed them into service still in UP colors.
In 1958 UP contracted with EMD to rebuild / upgrade F3 units with F9 mechanical components utilizing anything serviceable from the F3s. In February 1972, the UP Fâs were destined for trade-in but a deal was struck with power-short CRIP (Rock Island) and their F units were substituted in exchange for the UP Fs. CRIP immediately pressed them into service still in UP colors.