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Alray: 1943

Alray: 1943

March 1943. "An eastbound Union Pacific freight waiting in a siding at Alray, California. Coming up through Cajon Pass. The Santa Fe tracks are used by the Union Pacific as far east as Daggett, Calif." One of many images taken by Jack Delano documenting a Santa Fe freight train's journey from Chicago to California. 4x5 Kodachrome transparency. Office of War Information. View full size.


On Shorpy:
Today’s Top 5

Santa Fe and Union Pacific 1953

Santa Fe and Union Pacific dieselized the California lines in 1953 but the Southern Pacific stayed with steam until 1957-8

Big Boys and Challenger Mallets

Yes,the Union Pacific Challengers and later Big Boys ARE Mallets.

A Breath Of Warm Air

Others see Challengers, articulating boilers and Big Boys but what stands out for me are those those yellow Fruit Growers Express box cars.

In what now seems to be another life I remember opening them in December on a cold Railway Express platform in Baltimore, Md and feeling the the heat come out of a carload of Christmas gift boxes of oranges and grapefruit.

I never did figure out if the heat was caused by the fruit itself or just the remnants of the California sun but it was nice having a warm place to work the night away.

Additional data on locomotive


"In the 1930s, with freight traffic increasing, the Union Pacific Railroad had to use combinations of its 2-8-8-0 and 2-10-2 locomotives to get trains over the rugged grades of the Wahsatch Mountains. To stay competitive, a more powerful locomotive was needed to speed up the railroad and to reduce the rising cost of helpers and extra trains. The UP simply needed a locomotive that could climb the Wahsatch faster.

Arthur H. Fetter, the General Mechanical Engineer, had been designing locomotives for the Union Pacific since 1918, and had been responsible for the development of its 4-8-2 "Mountain" and 4-10-2 "Overland" locomotives as well as many other innovations and improvements to UP motive power. Fetter suggested a high speed articulated locomotive to reduce the reciprocating weight of a compound and to increase the 50 mph speed limit of the railroad's most powerful locomotives, the rigid wheeled 4-12-2s.

Fetter had a long standing working arrangement with the American Locomotive Company and he often collaborated with ALCO's engineers on locomotive designs. For the new more powerful locomotive he and the ALCO engineers started with the 4-12-2. They decided that the leading four wheel truck would be needed for better side control. They split the six sets of drivers into two groups of three and replaced the two 27" outside cylinders and the one 31" middle cylinder with four 22" x 32" cylinders. Two inches were added to the diameter of the boiler and the pressure was raised from 220 psi to 255 psi. The firebox was enlarged and they added a four wheel trailing truck to carry its added weight.

The first 4-6-6-4, UP number 3900, was received from ALCO at Council Bluffs on August 25, 1936, and after a brief ceremony it headed west pulling a refrigerator train."


"The Union Pacific Railroad took delivery of the very first locomotive with the 4-6-6-4 wheel arrangement in 1936 when it received 15 of them from the American Locomotive Company. These newly named "Challengers" were designated Class CSA-1.

In 1937, another 25 ALCO-built "Challengers" were added to the roster. This group, designated Class CSA-2, was given road numbers 3915 through 3939. They were similar to the Class CSA-1s. Six of them, numbers 3934 through 3939, were equipped for passenger service.

In 1942, ALCO delivered 20 Class 4664-3 "Challengers" which were numbered 3950 through 3969. The tenders on these locomotives were larger than either of the CSA classes.

In 1943, another 25 Class 4664-4 "Challengers" came from ALCO and were numbered 3975 through 3999. This group was very similar to the Class 4664-3s except that each weighed 6,500 pounds more.

A final 20 ALCO-built "Challengers" arrived in 1944 giving the Union Pacific a total of 105 of the 4-6-6-4s. These locomotives designated Class 4664-5 were similar to the Class 4664-3s except for an additional 7,500 pounds in the total weight. They were numbered 3930 through 3949 which required that the Class CSA-1 and CSA-2 locomotives be renumbered into the 3800 series."


The information above is consistent with data from published reference works on the topic excepting perhaps minor incidental details and slight adjustments of specific dates for specific engines, so far as I can verify. Interested readers may wish to locate and peruse such titles as The Challenger Locomotives / by William Kratville (Kratville Publications, 1980) for further information on the locomotive, or Union Pacific Motive Power in Transition 1936-1960 / by Lloyd Stagner (South Platte Press, 1993) for their utility and operational impact on the railway. An excellent photo study of this type, both the early and late engines, in action in various scenic locations is Union Pacific Steam, Challenger Portraits / by James Ehrenberger (Challenger Press, 1993)

As a final thought, I would only note a few things: one, this particular machine would have been oil-fired at the time and place of the photo; two, in 1944 it would be renumbered by the railway into the 3800 class, to avoid confusion with its later, more modern siblings; three, photos and extant records document these locos in service for both passenger and freight trains over this same line as in the photo on Shorpy; fourth, reefer (produce, or "perishables") trains were high value, spoilable products shipped as quickly as possible to avoid ruin enroute, so an excellent choice for such an engine; fifth, the engine is in the siding (note the smaller rail and lower ballast than the mainline), perhaps to let a higher priority train go by -- virtually the only trains with higher priority would have been passenger or "main" (i.e., troop) trains; sixth, the stack exhaust is showing only as a very slight haze & a mild disturbance of heat shimmer, meaning the firing is very clean and the tubes probably fresh, corroborating with the boiler paint's shiny finish (NOT the smokebox, which is "graphite" gray) that the loco has been freshly shopped; seventh, only a very mild steam exhaust is issuing back near the firebox, with no steam issuing from the pop-valves above the boiler, further evidence the fireman has everything pretty much under control; eighth, there is no steam exhaust from the cylinders, indicating the loco is at rest, which is consistent with other photos by Delano which appear to have been taken from on top of the reefers going up the hill on this run, and that this operational stop allowed him to explore another view, where he quickly found a classic image to exploit; last, this is one of the most beautiful photos of this locomotive, and of a locomotive on this line, and of this location with a classic westward-looking framing, color or b-&-w, that I've ever seen.

A couple of other UP notes

As others have said, this is an engine from the first set of Challengers, built well before the war. The second set, built after the Big Boys, had the same front end arrangement as the latter. UP 3985, the largest operable steam locomotive, came from that set.

If you look at the headlight closely you may notice that its visor is rather oddly shaped. This sort of half-conical shield was applied to a lot of west coast engines early in the war on the theory that it would make them less vulnerable to air attack, since less of the light was visible from the air. Personally I think the pattern of light on the ground would point back at the engine all the same, but at any rate, I don't believe it was ever used elsewhere in the country and it seems to have died out as the war progressed and the possibility of a Japanese attack faded.

I love this site

See, I can look at this pic and register "steam engine" and "boxcars". Other than that, I'm pretty much a dial-tone.

Then there's a comment, and another, then one disputing and correcting and the next thing you know, it's a Shorpster geek frenzy, and before you know it you've learned something.

Articulated locomotives. Whoda thought?

Still alive and very well

One of the Challenger locomotives, #3985, is still kept in operation by the Union Pacific Railroad, out of Cheyenne, Wyoming. Those of us fortunate enough to live along the mainline route of the UP have the thrill of seeing this magnificent engine in action when it passes by on its special excursions. Several years ago, #3985 was taken from being a static display and fully restored to operation by UP employee volunteers.

Old 395

ran parallel to the tracks. now it is I15. It was two lanes in 1943, now 6. When i was young in 1943 my parents had a desert shack on the eastern side of the hills near Phelan. I remember well watching the big steam engines on the grade. There were cabooses then, too.

OK, you get my vote

Anytime you publish a photo of a steam locomotive you have my undivided attention. Oh what a thrill the last generation missed of standing beside one of these monsters.

Its twin is still running

Another UP Challenger, #3985, was rebuilt by the volunteer work of UP employees in 1981 and is still active in public relations tours. This photo nicely illustrates the effects of World War II upon deferred maintenance of way. The Santa Fe would never have tolerated all those weeds under normal circumstances.

Flexible Flyer?

Well, first off, it is not a UP Big Boy, which were numbered in the UP 4000 series and had 16 driving wheels to the 12 driving wheels under UP 3931.

Although at home on freight, the UP 3900s were frequently used on passenger trains as capable of higher speed than a Big Boy 4000, the latter primarily a freight locomotive.

Both types of locomotive had two steam engines, the front one hinged so it could take curves, the rear engine fixed parallel with the boiler.

Two steam engines, ONE locomotive.

In these cases the boiler did NOT bend, but the Santa Fe DID have articulated locomotives in which the boilers 'bent' on curves, the front portion solidly fixed to the hinged front engine, the rear portion, with the firebox and the cab, fixed to the rear engine.

A maintenance headache, to say the least.

On the UP 3931 the headlight is mounted on the smoke box door on the front of the boiler, and, in this position will shine way out into nothingness as the locomotive rounds curves.

On many articulated steam locomotives including the Big Boy, the headlight was mounted on the front engine which followed the curves, the light beam then shining more directly down the track ahead of the locomotive.

In the spur to the right are two Maintenance of Way cars probably for the use of track employees. The nearest car is an old locomotive tender, the fuel once going in the opening facing the camera, the rest of the car being for water, in this instance the tender becoming a 'Water Car' which was filled at the same water towers as steam locomotives.

The car behind the old tender is an 'Outfit Car' in which workers would live while on the road. Note sloped steps up to center door, windows in side and a low stove pipe.

The aforementioned Water Car would contain water for their use.

The freight cars behind UP 3931 are refrigerator cars which, in this era, were cooled by blocks of ice put into bunkers at each end of the car.

The hatches at each end, propped open at an angle on some cars in the photo, are where the ice would be dumped in at Ice Houses next to the track.

Lovely Photo! Thank You!!


This isn't a Big Boy; it's a UPRR Challenger Class 4-6-6-4 wheel configuration, predecessor to the Big Boys. The Big Boys were 4-8-8-4 engines built primarily to service the steep and heavy Wyoming-Utah routes. Their numbers were 4000-4024. The Challengers did lighter freight and passenger lines across most of the UP routes, including Nevada and California. The later locomotives of this challenger class were numbered 3930 to 3999. All beautiful engines and this is a great photo!

Alray today

Clean Machine !

Looks like UP#3931 just got out of the shop.The paint is shiny enough to reflect the trackside off of the tender and boiler.It won't look like that in a month or so.

Motive power

The engine looks like a Union Pacific Big Boy one of the most powerful steam engines ever built designed specifically to haul war materials over the Sierras.


Wow, you can really see the articulation of the boiler in the curve. Delano must have been having a ball on that trip. Great photo in a beautiful place of an impressive machine.

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