Hi again. Happy New Year to y’all.
I got a question according the Big Boy.
I 've been reading a lot, I got a HO model of it too but there is this model of the “Cab Forward” Big Boy. I can find any info on the internet about these locomotives other than just in toy-scale. Do or did they in real life excist of is it just a scalemodel of something that would have been… ?
Two different locomotives. This should help:
The Cab Forward was not a Big Boy, but it definitely did exist. And, boy, was it big! They served on the Southern Pacific, their cabs mounted forward to protect crews from asphyxiation in the Espee’s many tunnels and snow sheds. I leave it to someone else to post pictures and provide a more complete explanation, but suffice to say yes they were real and unique locomotives.
The cab forward is a 2-8-8-4 (or 4-8-8-2) depending on how you count and is closer to the Yellowstone of DM&IR fame, though the models are not interchangible. I have never seen the cab forward but certainly have seen the Yellowstones and they are huge.
The California Railroad Museum (Sacramento, CA) has a Cab-forward on display (indoors) in their main museum. It’s a 2-8-8-4 rigged to run with the smokebox facing the tender, burned oil and the 160-odd samples were used in a lot of places on the SP system.
The Union Pacific Big Boy was a coal-burning 4-8-8-4 that was limited to Wyoming and a bit of eastern Utah. Only 25 were ever built, of which eight survive in various places.
Chuck (Modeling Central Japan in September, 1964)
In early 1981 the monstrous locomotive received a cosmetic restoration in the Museum’s restoration facility. It has been completely repainted and refurbished, and many of the missing parts replaced. Mechanically, the engine is in remarkably good condition; during the Museum’s cosmetic restoration, nothing was found that would preclude the possible restoration of the locomotive to operable condition at a later date.
[8D]
Bill’s right. Probably the only thing keeping the 4294 at the California State Railroad Museum from being put into operable condition is money. It’s in almost perfect condition.
The 4-8-8-2 Cab Forwards of the SP were built to run cab-first mainly because of the many tunnels and snowsheds on the “Hill”, otherwise known as the Sierra Nevada mountains of California. They proved so successful that SP kept the design through all 160 of the locomotives. They were rated at about 124,000 pounds Tractive Effort, and were designed by Baldwin to reach speeds of up to 70 miles an hour, if need be (though I don’t think any were actually pushed to that limit).
They could be run cab-first because being oil burners, the fuel could be pumped from the tender along the boiler to the firebox through a series of heated pumps.
There’s a bit of controversy as to whether the Cab Forwards were actually ‘backward’ Yellowstones, as the lead truck was designed as much for guiding the locomotive as it was to support the firebox and large all-weather cab. But if they are indeed ‘Yellowstones’, then they are the most numerous of that particular locomotive type ever built.
But like the 25 Union Pacific “Big Boy’s”, the Cab-Forwards were designed by and for a particular job on a particular railroad. Just as no other American railroad had a 4-8-8-4 ‘Big Boy’ except the Union Pacific, no other railroad had a 4-8-8-2 Cab Forward than the Southern Pacific. They were both very unique–and extremely successful at their particular jobs.
I grew up in “Cab-Forward” country–the Sierra Nevada of California, and they were huge, remarkable and beautiful locomotives. In fact, when I was a kid, I thought ALL Articulateds “ran that way”, LOL!
Tom [:)]
And you do not have to go out west to see one; Steamtown has a Big Boy. Stored outdoors and hopefully not rusting to pieces. [8D]
Art:
You bring up an interesting point in comparison. Actually, though they somewhat cosmetically resemble each other, the massive Yellowstones of the Missabe were not based on the SP AC series Cab-forwards, but actually on the Baldwin-built 251 series of 2-8-8-2’s built for the Western Pacific in 1931. Originally, the Missabe was thinking of a 2-8-8-2 wheel arrangement, however with the large all-weather cab required for cold temperature Minnesota running, the final design required a four-wheel trailing truck. Oddly enough, the firebox design for the locomotive was a bit smaller than the WP 2-8-8-2, but so efficiently designed that it provided even MORE tractive power. The Missabe Yellowstones could provide almost 145,000 starting TE (a little more than the Big Boy) and like the Baldwin built Cab Forwards, was designed for a 70mph maximum speed.
The locomotives turned out bigger than a Cab-Forward (and bigger than the WP prototypes), and in fact, were comparable in weight and stamina to the Big Boy’s, though they were designed specifically for a much different job–hauling heavy ore trains.
The Rio Grande borrowed about 8 of the Missabe Yellowstones during the winters of WWII for use on their Moffat Tunnel and Tennessee Pass lines, and reported to Baldwin that they were the best-running locomotives they had ever handled. There is a ‘rumor’ that if the design had not been ‘frozen’ by the government during the war that Rio Grande would have had duplicates built by Baldwin.
They were an INCREDIBLY successful locomotive. And you’re right–they were MONSTERS! [:P]
Well, I still need to go west quite a distance, because I am in Europe…
the 4-8-8-2 design is an enhancement from the 2-8-8-2 cab forward, because a 2 wheel “pilot” truck did not track that well and did not ride that well, so a 4 truck design was tried. History.
…wonders if the “Friends” would consider that engine…
The only commonality between a Big Boy and a Cab Forward is that they are both Mallet type locomotives aka articulated tow actually engines sharing a common boiler. The reason the Cab Forward idea was born was to avoid asphyxiation of the crews. Originally the SP had used a pair of conventional 2-8-8-2 mallet locomotives to pull large trains over the 150 miles of Roseville-Sparks line over the Sierra Nevada mountains most of which were 2-1/2% grade, but found that by exerting so much power they blew the roofs of of snow shed and almost killed their crews because they put out so much smoke especially going through tunnels. So an enterprising engineer turned the mallet and hooked it pilot to the front of the train. This solved the smoke problem but lead to even more serious ones of the tenders pushing the locomotive that would have surely resulted in derailments. Baldwin built a total of 47 Cab Forwards sold exclusively to the SP. At first the crews were reluctant to accept the new design for fear of what may happen if by change they hit something like a gasoline tanker truck stalled on the tracks but eventually they saw the advantages far outweighed the disadvantages. This scenario could have never been played out with a Big Boy as everyone ever built was a coal burner where the CF was an oil burner.
Hmm…
I have understood to date that there are two main types of steamers based on platform and engine placement under the platform…fixed frame and articulated. In the articulated category, come simple steam and Mallet types. The latter is characterized, not solely by its articulated function, but chiefly because it uses steam twice…scavenged from the exhaust of the rear simple steam cylinders, and routed forward in ducting to be used as expanded and cooled steam in the much larger forward cylinders…which happen in most cases to also be mounted on an articulated frame member.
So, a Big Boy and a Challenger are not technically Mallets, where the Y series made by the Norfolk & Western are Mallets because of their use of expanded steam in the forward cylinders. Not so the Big Boy.
I am not confident in the veracity of this article in wikipedia, but in the paragraph headed “Simple Expansion” further down the page, the various contributors seem to support my contention.
http://en.wikipedia.org/wiki/Mallet_locomotive
-Crandell
Not really. The four-wheel truck under the firebox on the 4-8-8-2 cabforwards was primarily to support a larger firebox which produced higher pressures and greater sustained volumes of steam so the locomotives had more horsepower, although a 4-wheel leading truck was handy because the locos were designed for moderately high speeds. The cabforward 2-8-8-2 locos were never converted to carry a four-wheel truck. They were eventually converted to simple-steam locomotives from compound-steam because compound locomotives were slow. The 4-8-8-2 locos were built with simple steam.
Also, SP’s cab-in-back 2-8-8-4 locos never had a lead-truck conversion even though they were capable of speeds at least as high as the 4-8-8-2 locos.
On the other hand, SP’s 2-6-6-2 cabforwards were unstable and were converted within months to the 4-6-6-2 wheel arrangement. In later decades there were also converted from compound to simple steam.
Mark
Crandell:
You’re right, the Big Boy, Cab-Forward and M-3/4 Yellowstones discussed are simple articulateds and not Mallets in the way the N&W compound Y’s were.
Oddly enough, SP engineers often referred to the Cab-Forwards as “Malleys” whether they were the newer simple AC-4’s and up, or the earlier compound 2-8-8-2’s (before they were ‘simpled’ in the early 1930’s). It was just a ‘generic’ term, according to my great Uncle Tom, who was an SP fireman.
But then, SP also referred to their 2-10-2’s as “Dec’s”–Decapods–so they wouldn’t have to call them “Santa Fe’s”, LOL!
Tom [:)]
If memory serves, the SP had three orphan, true Decapod, 2-10-0 locomotives (SP-classified “Decapod”). These locomotives were disliked and were soon retired. If these locomotives had a nickname, I doubt it could be repeated on this family-oriented forum.
Mark
Technically speaking all articulated locomotives are Mallets named after the Swiss inventor Anatole Mallet (pronounced Mallay) The “mallets” other unique design characteristic was that they were compound locomotives (using steam twice ). A common misconception or origin or many and argument is being as Mallet designed the locomotive specifically for the N&W that only their locomotives were of the Mallet type and not the other railroads that used articulated designs
The compound argument that a Big Boy is not a Mallet type locomotive is just a matter of splitting hairs.
It’s like saying Karl Benz the person credited with the invention of the first gas powered car that all automobiles should be called Benz’s or should all TV’s be called Dumonts? Be
Mallet’s patent specified compound use of steam.
Non-compound articulated locomotives have more complicated steam and exhaust systems than the Mallet. They also have different operating characteristics.
Mark
Actually, there are THREE main types of steam locomotive designs, depending on whether all, some or none of the driver sets are fixed in the frame that supports the boiler.
Let me confuse things a bit more.
Here is a model of what can be called a “Duplex” locomotive in which another set of drivers is placed under the tender such as pictured. These were Dick Truesdale’s (of Westside Models) favorite locomoties having five of them providing maintstay motive power for his layout. For the prototype (which was coal powered and pictured at the bottom of this message), two Mikado locomotives were modified to provide steam to a set of drivers under the tender from retired Consolidations. A couple of other railroads had several “Triplexes” which were Mallets constructed with an extra set of drivers under the tender.
My Avator is a photo of a South-African-built Garratt-derivative. Instead of having the frame articulated into three parts, this locomotive’s frame is only articulated in front of the boiler under which the front set of drivers are. The rear sets of drivers are set under the frame holding boiler, cab, and fuel, and which swivels like those under normal geared locomotives.
Mark