Steam & Excursion > Did UP Big Boys have a Booster on the trailing truck ?

I never heard this mentioned on any UP  Big Boy information,   But did any of the 4000 class have a Booster on the trailing truck?  To me it seems
like it would be a good idea, to help starting heavy trains.

Trainman41 Wrote:
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> I never heard this mentioned on any UP  Big Boy
> information,   But did any of the 4000 class
> have a Booster on the trailing truck? 

No. Neither did the Challengers nor the FEFs.

To me it
> seems
> like it would be a good idea, to help starting
> heavy trains.

Your joking! You don't think that the 4000 and 3900 class locomotives had enough starting tractive effort?

HotWater Wrote:

> You don't think that the 4000 and 3900 class locomotives had enough starting tractive effort?

So long as the drawbars can take it, is there such a thing as "too much" starting tractive effort?  

Evan_Werkema Wrote:
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> HotWater Wrote:
>
> > You don't think that the 4000 and 3900 class
> locomotives had enough starting tractive effort?
>
> So long as the drawbars can take it, is there such
> a thing as "too much" starting tractive
> effort?  

Not really. The UP 4000 class locomotives had over 135,000 pounds of TE. Modern AC traction diesel electrics have over 170,000 pounds starting TE. So long as the application of starting power is smooth, with no wheel slips, the train couplers stay together. As additional information, when the new EMD SD70MAC units began showing up in quantities, the reports of broken knuckles/drawbars dropped dramatically in the Powder River coal hauling territories.

The current electronics limits the acceleration rate of the locomotive. A drag race between an SD45 and
an SD70MACe would be laugher until the horsepower of the MAC finally caught up. That rate limit was
always why people complained about how slowly a GE would load. Now with electronic injection that
fuel that used to be smoke can be modulated on a start. 

Out

callum_out Wrote:
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> The current electronics limits the acceleration
> rate of the locomotive. A drag race between an
> SD45 and
> an SD70MACe would be laugher until the horsepower
> of the MAC finally caught up. That rate limit was
> always why people complained about how slowly a GE
> would load. Now with electronic injection that
> fuel that used to be smoke can be modulated on a
> start. 
>
> Out

Sorry but, you have no idea what you are talking about!

So, GE didn't use acceleration control to modulate smoke? I just use acceleration control as a
general term since the "computer" uses a number of variables. And as to my industry experience,
I've got about as much as you have.

Out 

callum_out Wrote:
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> So, GE didn't use acceleration control to modulate
> smoke? I just use acceleration control as a
> general term since the "computer" uses a number of
> variables. And as to my industry experience,
> I've got about as much as you have.
>
> Out 

Not on EMD AC diesel electrics! I spent many years out on the BN/BNSF  Powder River coal trains out of Gillette, WY training Engineers on the capabilities of AC traction. The GE units at that time couldn't come close. Plus, it was NOT about attempting to "modulate smoke"..

I'm talking about the improvements made to the Dash 7 upgrades from the U series. The ACs are a whole
different animal. Check any logic diagram on an EMD AC and you can see where the system controls the rate
at which the locomotive loads and in the broad sense of my term-acceleration control. The modular system on
the SD45 was a huge step forward but put 4 on a beet train and best wait for the helpers to load first. I've
heard that an SD45 would reach 60 mph (light engine) in a mile or so. Without a true load loop input you
need to control that initial rate.  

Out 

Trainman41 Wrote:
-------------------------------------------------------
> I never heard this mentioned on any UP  Big Boy
> information,   But did any of the 4000 class
> have a Booster on the trailing truck?  To me it
> seems
> like it would be a good idea, to help starting
> heavy trains.

I don't know what locos have or had boosters EXCEPT the 4449 (4-8-4) at the ORHC has one while the SP&S 700 (also a 4-8-4 and also at the ORHC, does not).  Doyle McCormack told me that in all his years since he has been asssociated with the 4449, he only used the booster two or three times.  Because of the fuel usage, it was only used when absolutely necessary.  I'm sure  there are other TO readers who know a lot more about this than I do as Doyle and I only had a short conversation about it and he was struggling to remember the number.

JOHN



Edited 1 time(s). Last edit at 11/15/25 20:48 by Jsporseen.

To OUT and others, Like the late Wes Camp, Hot Water, in my opinion is the absolute expert in steam and diesel matters. He worked with EMD for many years trouble shooting new power during the late 1970's until he retired. He also an intergal member of the AFT on the #4449 as a fireman and engineer and other main steam locomotives.  He may have more miles unders steam and diesel thaan anyonwe I know.  Just my 2 cents.  Highball Jack!

1522 was booster equipped and it came in handy a couple of times. I also would use it once in a while just to keep it limber.

Explain what a booster is

Pretty good description here -

https://en.wikipedia.org/wiki/Booster_engine

dougd Wrote:
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> Explain what a booster is

Basically, a small two cylinder steam engine hung/mounted on the trailing truck frame, driving a crankshaft that has a pinion gear on the end of the crankshaft. The pinion gear is moved by air pressure to engage a large bull gear mounted on the axle. When engaged and powered, the Franklin Railway Supply booster can provide about 12,000 pounds of additional tractive effort for starting. Disengaging the booster at about 25 MPH takes place when the Engineer begins to "hook up" the power reverse gear as speed increases.

dougd Wrote:
-------------------------------------------------------
> Explain what a booster is

Video Here

Mary McPherson
Dongola, IL
Diverging Clear Productions

Okay...I will stay out of the "technical discussions" about boosters and SD45's. The booster on the SP4449 was not used much at all, but one of the times it was used I was firing the engine! I remember Doyle telling me to have her hot (300 pounds) and put a little more water in the sight glass. when he cut in the booster to start (can't remember where) the whole floor of the locomotive shook! It definitely helped getting the train moving! On the SD45 discussion; I'm an SP guy so I ran SD45's all of the time. The last year the Southern Pacific used the trackage rights they had over Altamont Pass on the sugar beet trains was either 1990 or 1991 without checking my time books. The power was 4 SD45's on generally 8000 to 9000 tons on old friction bearing beet racks made in 1947 and 1949. The Altamont is a 1 percent grade piece of railroad, old WP then UP. On one trip I had to set out a beet rack that had a hot box. The 4 SD45's  got the tonnage moving again on the grade. There were never any helpers on this 1 percent grade. They were great engines and had 0ne thing that I noticed. In working grade territory, say Donner east of Roseville, Calif. If you had all SD45's say on the Altamont grade the sound was a definite rumble with these locomotives. If you had say 4 or 5 SD40's on the same train you would get more of a scream. I guess that might have been the difference between a 16 cylinder engine block and a 20 cylinder engine block. This just my own experience!

Craig

Following up on Craig's post above, to the best of my memory, the longest that the booster on 4449 was ever used was leaving Danville, VA with the American Freedom Train. The town of Danville is situated in a bowl, and the Southern Rwy main line is up-hill in both directions out of town. We were scheduled to depart southbound, well after midnight, after the train was reassembled. While the train was being assembled, a manager from the Southern Rwy showed up and informed us all that the Southern would NOT be able to provide a diesel helper in order to assist us leaving town on the ascending grade. However, he was going to have the entire Freedom Train pulled northward up the descending grade into town, thus 4449 would be able to start on the down grade and accelerate through the station on the southbound main track and thus have a "running start on the grade southward.

Although it was raining pretty heavily, we completed the air test and given a highball to head south. Down the grade we came and Doyle had her wide open in order to build up speed. heading through the station, which was also a main line fueling station for Southern Rwy passenger trains, at 30 to 40 MPH we were on the ascending grade. What with the various street grade crossings, 4449 began to slip on each crossing. Our speed was dropping quickly, and Doyle had a hell of time working the throttle in order to recover from each slip of those big 80 inch drivers.I could seed Doyle warming up the booster, and finally engaged it. By then we were down to 10 MPH in a heavy driving rain, but she didn't slip any more after the last street crossing.

I don't know, or remember how long that grade was but, we spent about an hour and a half at 10 MPH, at full throttle and the booster engaged. After  about a half hour, we began to experience a strong odder coming up through the cab floor. We finally figured that the booster was getting pretty hot and all that old Bunker C from the old days, was melting on top of the booster case. Man what a stink!

Later in the early morning before sun rise, we had to enter some sort of State Park (near Charlotte, NC) but, nobody told us about the steep grade into the park. Track speed was only about 15 MPH on the little used branch. We began slowing down so Doyle worked more and more throttle, until he had her wide open. We kept slowing down, so he engaged the booster again, but we still kept going slower and slower, until we finally stalled,,,,,,,,,,,,with a wide open throttle and booster! She never slipped a bit, but just simply stopped. The Pilot Engineer then explained, "Nice job guys! However a diesel is only rated for 1500 tons on this grade.". The set of diesel on the other end of the train pushed us the rest of the way into the park. Doyle had had enough!

Great story Hotwater. I was following along as I read each word, I was in Danville yesterday and I could visualize the moment you were blasting through town.

Thanks for another wonderful story.

Ed

Posted from iPhone

One of the times that Daylight 4449 definitely used its booster was going northbound through Chicago Union Station with the AFT in 1975.  Glenn Brendel, founder of the FWRHS and a long time NKP fan, knew Doyle from the NKPHTS.  Doyle told Glenn to show up at Aurora, IL and ride through Union Station and north on the C&NW to Green Bay for its next exhibition.

Glenn brought a 24 year old pup along and we rode either the cab or the tool car all the way to Green Bay.  There were excruciating slow orders on the BN triple track due to clearances between the low level bridges and the full width pilot on the 4449 (or was it the width of the cylinders?).  The routine was to walk it through the tight clearances, then speed up all he could until the next bridge, walking speed again, and then rinse and repeat all or most of the way to Union Station.  Arrival in CUS was midnight or later and there was heavy fog.  The strobe lights on the Sears tower were absolutely eerie in the night fog.  The rail was slick, so while on the through track near the river the 4449 bogged down. After stopping, the booster was engaged and it was an amazing sound show in the middle of the night at walking speed. There was nobody there to watch the show!  Mid-day we bogged down on the northbound grade at Sheboygan.  We had to stop, back up, and make a run for the hill.  It too was a helluva show but I am not sure if we used the booster again.

The preferred spot to hitch a ride on the 4449 was to sit in the "cat bird seat" at the front of the tender in the middle and up high.  You were out of the way of the operating crew but could see everything going on.  Upon arrival at Green Bay, we jumped into Glenn's auto for the return drive to Fort Wayne.  An AFT employee gladly drove Glenn's car from Aurora to Green Bay rather than ride  the unpredictable train.