About the Prototype
first 20 engines of this class numbered 800-819 were delivered to the
Union Pacific from ALCO in 1938. These were to replace the then dominating
4-8-2 UP steam power with increased efficiency and higher operating
speeds. A further 15 units numbered 820-834 followed a year later,
equipped with larger cylinders , larger drivers and "centipede" tenders
instead of the original 6 axle tenders.
locomotives were referred to simply as FEF's which stands for "four-eight
-four" which is their wheel arrangement. The first batch of 20 engines
became the FEF-1's, the second order FEF-2's and the final batch of ten
engines delivered in 1944 were FEF-3's , numbered 835 - 844.
FEF's were coal and oil fired depending on their division assignment. The
war effort converted many oil fired engines to coal, then back to oil
firing again after war's end. These locomotives were able to operate at
100 mile sustained speeds on designated sections of track. The newly
designed tapered coupled rods with forked rod ends and separate sleeved
bearings better absorbed the thrust and pull forces of the fast
reciprocating mass of steel. The operational speed for this design was
limited to 110 miles per hour.
FEF's were primarily entrusted with express trains carrying passengers,
mail and perishable goods. In the mid 1950's Diesels started to appear
more frequently on the head ends of such trains and the FEF's eventually
retired from service, most of them going directly to the scrap yard.
However, publicity conscious Union Pacific saved engine 844 and kept here
serviceable until today for frequent performances with steam fans and
other public relations service. Other UP FEF's escaping the cutting torch
are # 814 in Council Bluffs and # 833 and #838 in undisclosed locations.