Union Pacific 800-class 4-8-4s on Cajon Pass

This page was last updated on May 5, 2016.

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There were three classes of 4-8-4 steam locomotives on the UP.

UP 800-819 were built in 1937 as coal burners with 77-inch drivers.

UP 820-834 were built in 1939 as coal burners with 80-inch drivers and full 7 axle centipede tenders.

UP 835-844 came in 1944 as coal burners with 80-inch drivers, similar to the FEF-2's but with double stack and different front end pilot.

The first conversion to oil started with 807 on March 10, 1946. Originally this was in response to the threat of a coal strike, but it enabled the FEF's to run for the first time down the oil burning South Central District to Los Angeles over Cajon Pass. All the FEF's were converted to oil by the end of 1946.

Based upon published sources, the UP 800's did not journey into Los Angeles (and therefore over Cajon Pass) until March 9, 1946 on the new passenger train Transcon. The last scheduled use in passenger train service occurred on July 18, 1948 for a total 'Cajon Pass exposure time' of 832 possible days. During this time, their appearance did change.

Dick Harley adds: Only oil fuel was available in Los Angeles. UP Mechanical Department records indicate that UP 807 was converted to oil on March 10, 1946, but the first train into Los Angeles with an FEF (presumably not oil) was on March 9, 1946. (Dick Harley, email dated July 10, 2015)

Ending the timeline in July 1948 was based upon 'regular scheduled use' and the date came from Chard Walker's books. Specials and unusual circumstances are always exceptions to 'standard use'. Not all the locomotives I listed necessarily ran over Cajon Pass, the photos were taken all over the UP system. I was trying to show how gradual appearance change occurs and how late I can run the FEF3 in black without mars and smoke lifters and still be historically accurate. (Robert Rogers, May 10, 2005)

(These later sightings include three in 1949 and one in 1950.)

The last date on Mr. Rogers' listing of July 18, 1948 correlates nicely with the continued delivery of Alco FA/FB diesel freight units. It also matches UP President George Ashby's statement to the UP Borard of Directors that the entire railroad west of Green River, Wyoming, would be fully dieselized by January 1, 1949, due to the completed delivery of the Alco cab units, and even more EMD F3s. That event was delayed for at least a year, but the reassignment of modern steam passenger power to the east in late 1948 to early 1949 was a direct reflection of both that stated goal, and the continued delivery of new diesel locomotives. (Don Strack, May 10, 2005)

The arrival of diesel freight units would allow steam freight locomotives to be moved east, reducing the need for steam facilities used by steam passenger power. The reduction of steam facilities was then used as a reason to replace steam passenger power with diesel passenger power on all trains, not just the Streamliners. Nothing happens in a vacuum. Everything is connected. (Don Strack, May 12, 2005)

(Based in part on emails to the Cajon Yahoo discussion group in February 2004 and May 2005).

Photo Research

Black Engines

Date Engine Mars-Light Smoke-Lifters Source
1946 801 no no UP484's
1-28-46 808 no no UP484's
3-9-46 805 no no LA&SL
4-46 842 no yes UP484's
7-4-46 828 no no UP484's
8-8-46 822 no no UP484's
9-2-46 844 no yes 8444
9-5-46 810 no no UP484's
9-8-46 816 no no UP484's
9-15-46 824 no no UP484's
11-10-46 837 no no UP484's

Gray Engines

UP began to paint passenger steam locomotives into a two tone gray paint during 1946.

The FEF-3's got the smoke lifters first. The Mars light came in 1947, the gray paint came in late 1946. They worked secondary passenger trains on Cajon Pass.

Date Engine Mars-Light Smoke-Lifters Source
5-17-46 809 no no UP484's
7-2-46 827 no no UP484's
8-5-46 807 no no UP484's
6-46 836 no no Mty800's
8-46 836 no no Overland Rte
8-7-46 821 yes no UP484's
9-2-46 827 unk yes  
9-2-46 806 no no UP484's
9-29-46 815 no no UP484's
10-20-46 821 no no UP484's
10-22-46 817 no no UP484's
11-13-46 822 no no RRTCP
11-46 839 no yes Overland Rte
11-11-46 836 no yes Mty 800's (Portland)
11-17-46 804 no no UP484's
1946 819 no no UP484's
1946 805 no no Mty 800's LA
1946 821 no no Mty 800's LA
1-5-47 831 no no UP484's
5-6-47 844 no yes 8444
5-10-47 831 no no LA&SL
5-25-47 844 yes yes UP484's
5-47 823 yes no TLOFGSta.
6-1-47 838 yes yes TLOFGSta.
6-27-47 836 yes yes UP484's
6-47 836 yes yes LA&SL
6-47 841 yes yes Mty800's
8-47 830 yes no LA&SL-Transcon
8-17-47 826 yes no UP484's
9-1-47 811 yes no UP484's
9-22-47 835 yes yes UP484's
9-27-47 833 yes no UP484's
9-28-47 820 yes no Mty800's-Cajon
11-12-47 800 yes no UP484's
11-47 814 yes no RRTCP
11-47 844 yes yes Mty800's-Cajon
11-30-47 809 yes no UP484's
7-18-48 830 yes no CRPTP
1949 829 yes no  
1949 843 yes yes  
6-19-49 844 yes yes  
5-25-50 811 yes no (last 800 seen on Cajon)

Source Codes

CRPTP = Cajon Rail Passage to the Pacific

UP484's = Union Pacific 4-8-4 photo books UPRHS

8444 = Union Pacific 8444

LA&SL = Los Angeles & Salt Lake by Signor

TLOTGSta. = The Last of the Great Stations (LAUPT)

Mty800's = The Mighty 800's by Kratville

RRTCP = Railroading Through Cajon Pass

Overland Rte = Overland Route pub by Carstens