Steam & Excursion > BB: DM&IR 'Yellowstone' at work ('55)

DM&IR 2-8-8-4 #235 6 miles south of Forbes, MN on June 17, 1955 .... by Bruce Black.



Edited 1 time(s). Last edit at 11/03/19 07:11 by valmont.

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A beautiful chunk of iron.  I wonder where the ore came from to build that machine ?  I saw one of the last ones run.

Craig Hanson
Vay, Idaho

What a great "Beastly" Beast!

Jim Baker
Riverside, CA

I like the bell and yoke mounted on the rear (back deck) of the tender...for reverse moves😁

Both engines are nearly in-synch,  a common result on articulateds when pulling hard... the physics of the power impulses, and the strain on the drawbar tends to pull the front engine into coordination with the power atrokesof the rear engine.

The  ‘lighter’ weight on the front axles, combined with maximum cylinder pressures causes the wheels ( not on sand)
to “quarter-slip”.   Quarter-slip occurs because the power applied partially exceeds the adhesion.... 
When both sets are in-synch, the pull against the load is successful in acceleration—- similar to boat racing crews while rowing..

Engines may get out of synch depending on the terrain’s hills etc, and thus, the great power being applied will allow the front engine to quarter-slip ahead by several degrees .....then under consistent loading , the 2 engines will revert to synchronization.
Again, the KEY here is the great load agisinst the tender’s drawbar.

Note also the ‘clean-stack’...a clear indicator of a well constructed fire-bed and 100% combustion of the carbon-gasses.
released under the intensity of a 3,000 deg. fire.   That ‘stack color’ is the surest indicator of a white-hot firebox...
and BP will be right at the max, as well as generating very intense,  superheated steam to the cylinders.

What a wonderful photo ....if you were trackside, the noise would be deafening!!!!
In synch, you’d hear the sound as if there was only one, two-cylinder engine working...
here, all 4 are exhausting in rhythmic unison ...

​W.

 



Edited 1 time(s). Last edit at 11/03/19 14:40 by wcamp1472.

An absolutely spectacular photo!
Thanks for sharing,
SR2

Wes, thanks for those notes about that syncronization of the articulateds engines.  It makes sense.  I wonder who must have actually observed this fenomenone happening ?  With all the fancy camera gear out there now a days, it would fun to record it, and  watch this happening.  I wonder what they did to figure this out ?   It seems like it would be fairly difficult to watch it happening.

Craig Hanson
Vay, Idaho

 

wcamp1472 Wrote:
-------------------------------------------------------
> I like the bell and yoke mounted on the rear (back
> deck) of the tender...for reverse moves😁
>
> Both engines are nearly in-synch,  a common
> result on articulateds when pulling hard... the
> physics of the power impulses, and the strain on
> the drawbar tends to pull the front engine into
> coordination with the power atrokesof the rear
> engine.
>
> The  ‘lighter’ weight on the front axles,
> combined with maximum cylinder pressures causes
> the wheels ( not on sand)
> to “quarter-slip”.   Quarter-slip occurs
> because the power applied partially exceeds the
> adhesion.... 
> When both sets are in-synch, the pull against the
> load is successful in acceleration—- similar to
> boat racing crews while rowing..
>
> Engines may get out of synch depending on the
> terrain’s hills etc, and thus, the great power
> being applied will allow the front engine to
> quarter-slip ahead by several degrees .....then
> under consistent loading , the 2 engines will
> revert to synchronization.
> Again, the KEY here is the great load agisinst the
> tender’s drawbar.
>
> Note also the ‘clean-stack’...a clear
> indicator of a well constructed fire-bed and 100%
> combustion of the carbon-gasses.
> released under the intensity of a 3,000 deg. fire.
>   That ‘stack color’ is the surest indicator
> of a white-hot firebox...
> and BP will be right at the max, as well as
> generating very intense,  superheated steam to
> the cylinders.
>
> What a wonderful photo ....if you were trackside,
> the noise would be deafening!!!!
> In synch, you’d hear the sound as if there was
> only one, two-cylinder engine working...
> here, all 4 are exhausting in rhythmic unison ...
>
> ​W.
>
>  

Yes thanks wes, your detailed synopsis really brings life and feeling to a still photo.
I saw your email reply to this post while delivering pizza (my Sunday job), couldn't read it then of course, and saved it till now to be able to sit down, read, and learn!

My question is, does the crew in the cab feel all this In sync/out of sync thing going on with both engines?, I'm sure they probably do? In the form of rocking from left to right being greater when both engines are in sync, as opposed to less rocking if both engines are out of sync?

I agree with Craig, it would be something to record this all happening somehow.

Jim Baker
Riverside, CA



Edited 2 time(s). Last edit at 11/03/19 23:49 by RailRat.

With a heavy load behind the tender, such gyrations are greatly reduced.
With light to no loading, the eginine bounces around like tractor-trailer, with no trailer!

The heavy load really smoothes-out the vector forces and centers the restraint on the drawbar pins between the engine and tender.   Another factor is the nearly-solid compression of the draftgear springs on the tender and the first dozen, or so, cars.
With light loading, at certain track velocities  and driver rotative-speeds, the drawbar springs and piston thrusts can get into a natural oscillation frequency —- in which the engine and cab wobble rhythmically.
With a good, heavy train—- all that bouncing smoothes right-out.  

The engines are built to generate immense amounts of steam while under a heavy draft up the stack, a heavy weight behind the tender,  and violent fire in the firebox.  The trick to firing is to only burn a little fuel and burn lots of air.... oxygen is a small component of the air through the grates.. the greatest proportion of air is inert Nitrogen....its oxygen that does the work....
thus, producing a stack which is mostly a light-gray cloud of cooled-down cinders...as in this picture..

So, the crew is REALLY enjoying this ride, tremendous  power and thunderous cacophony assaulting all the senses...
”You know you were really Haulin’ The Mail”! In the words of a famous astronaut* on a Saturn IV B rocket ride...

​W.

* Neil,Armstrong?



Edited 4 time(s). Last edit at 11/04/19 12:50 by wcamp1472.

I've heard or read somewhere these locomotives were the largest and heaviest in the world. 

Re: hawkinsun, above

He asks about video of ‘synchronization’..like we were discussing...
I had seen  chase video of UP 3985 up close and for a long time ...next to the engine ....it went into full-synch, stayed there for about 30-or so revolutions then went out...

So there is chase video available where you can see that happening...I think it was a return segment on the way back  to Cheyenne..

Some of the 3985 crew members might be able to relate if they were aware of that as it occurred..
Jack?

​W.



Edited 1 time(s). Last edit at 11/04/19 14:42 by wcamp1472.