WEIGHTING A LOCOMOTIVE PART 2

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Harold_V
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Re: WEIGHTING A LOCOMOTIVE PART 2

Post by Harold_V » Tue May 17, 2016 3:15 pm

Trainman4602 wrote:The weight of the locomotive remains the same it is just distributed differently.
Obvious to those of us who understand WHY equalization became a part of loco construction.
I now have more weight on the drive wheels . That's where I want the weight.
As the old cliché goes, the proof of the pudding is in the eating.

Well done, Dave.

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.

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johnpenn74
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Re: WEIGHTING A LOCOMOTIVE PART 2

Post by johnpenn74 » Tue May 24, 2016 10:57 pm

JJG Koopmans wrote: Sorry, if you adjust a spring hanger nut you introduce an extra vertical load which affects all the other ones. Textbooks on locomotive design are full of the proper theory and the way to work with it.
Kind regards
Jos Koopmans
I believe you are confusing equalized with unequalized suspension systems. If you took an unequalized 0-6-0 and adjusted the middle axle hanger nuts, we could add so much verticle lift to the spring we could put the whole weight of the engine of the middle axle. Sure you would be redistributing the weight to just the one axle. This the same things with adjusting suspension on 4 point automobile suspension. Cars are independent on all four points and yes, we can adjust the travel of any one of the suspension arms and remove it from touching the ground if we add enough shims or shorten shackles etc...

Equailzed systems will NOT allow you to do this by virture of the way they are designed.

None of this unequalized stuff applies as the K4 in discussion is a EQUALIZED 3 point suspension system IE:
1) 4 wheel lead truck
2) left side drivers and trailing truck
3) right side drives and trailing truck]

The only way to add more or less weight to the 4 wheel lead truck is to move it closer to or away form the center of mass. 2 wheel lead truck will allow you to change the fulcrum pin under the cylinders and actually shift load on or off. 4 wheel you can't do this. The equalized weight on the drivers and trailing truck remains the same. Even if you change the equalizer fulcrum pins between drivers or between the driver and trailing truck you will not move any weight to or from the lead truck. The levers just don't work that way.

Dave, Have you changed out any of the springs on the drivers?

JP
John Pennington

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2 Mich-Cal Shays
Allen 4-4-0 Narrow Gauge Conversion
Reading A5a Camelback 0-4-0
USRA 0-6-0
Clishay
4 Western Wheeled Scraper NG Dump Cars
N&W 4-8-2
ICM 2-10-2
4 Modern Stake Cars
L&N Caboose
4 Big Four Conversion Gondolas

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GS14403
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Re: WEIGHTING A LOCOMOTIVE PART 2

Post by GS14403 » Tue May 24, 2016 11:43 pm

When a locomotive with rockers enters a curve the rockers lift weight off the locomotive drivers due to the fact that generally the leaf springs on the lead and trailing trucks are built to scale and are too stiff to compress. I have seen the drivers on my 4-8-4 stop turning when traversing a track that has a dip deep enough to cause the drivers to come off the ground while the lead and trailing truck leaf springs act like solid blocks. In my case adding coil springs to the rear of the suspension, in place of the prototype solid anchor at the trailing truck, and at the lead truck has reduced the effects of rocker lift. At the lead truck approximately 1/4" of metal was removed between the locomotive frame and the mounting plate on the lead truck to allow for the coil spring to compress. These two modifications has drastically reduced driver slippage on curves and rough track.

My leaf springs are made to scale which makes them too stiff by a large margin. Any one of my springs would take over a thousand pounds of pressure to barely deflect. That is the price I paid for having scale springs. Fortunately the coil spring additions are well concealed and do not distract from the appearance of my locomotive.

Here is a photograph of the modified lead truck rocker and frame mount assembly, near the bottom of the page.
http://www.chaski.org/homemachinist/vie ... 7&start=12

And about 1/3rd. and 2/3rds. down on this page.
http://www.chaski.org/homemachinist/vie ... 7&start=24

Hope this info helps in visualizing the problem and my cure.

Donald

SP&S700
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Re: WEIGHTING A LOCOMOTIVE PART 2

Post by SP&S700 » Wed May 25, 2016 3:13 pm

GS-1

I was trying to see from your "Finishing up the Hard way" where your springs were. First I had to go by your cylinders and valve chest. Which is really neat, and I hope I live long enough to steal your idea. Love the curved pipes. With the right track, load and grade she ought to sound wonderful. Also I think we discussed, that you buck the trend on cylinder bore, which I also like. I don't suppose you could give a quick lay out of how / in what order you welded the chest up?

Thanks

Clint

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johnpenn74
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Re: WEIGHTING A LOCOMOTIVE PART 2

Post by johnpenn74 » Sun Jun 05, 2016 10:43 am

GS14403 wrote:When a locomotive with rockers enters a curve the rockers lift weight off the locomotive drivers due....
No, this is not true... If you have solid blocks of steel instead of springs, the vertical lifting of the heart rockers (1/4 - 3/8... whatever) does not take more load. It doesn't matter if you lift the frame vertically an inch. So long as your suspension is not bottoming out or binding the rockers, driver leafs, etc with tilt, equalize but their over all load remains the same. This concept of lead trucks shift load is false. Give me a sec.... I'll prove it mathematically.

If your load shifts, its because something is bottoming out, or binding...

I will grant you, that you will break loose and slip for springs are too stiff, but it has nothing to do with load transfer on an equalized locomotive.

JP
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John Pennington

Project
2 Mich-Cal Shays
Allen 4-4-0 Narrow Gauge Conversion
Reading A5a Camelback 0-4-0
USRA 0-6-0
Clishay
4 Western Wheeled Scraper NG Dump Cars
N&W 4-8-2
ICM 2-10-2
4 Modern Stake Cars
L&N Caboose
4 Big Four Conversion Gondolas

Like I'm actually gonna build all this stuff :-P

JKreider
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Re: WEIGHTING A LOCOMOTIVE PART 2

Post by JKreider » Sun Jun 05, 2016 2:24 pm

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Last edited by JKreider on Wed Jun 08, 2016 8:30 pm, edited 1 time in total.

SP&S700
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Re: WEIGHTING A LOCOMOTIVE PART 2

Post by SP&S700 » Tue Jun 07, 2016 1:41 pm

Your Kidding Right!

One can you print your math please and formulas so one can see them and then could we see your variables (define them).

I'll try to attack it this way. Have you ever driven a front wheel drive car up hill with a load in the back? Now how does a rear wheel car perform with load in the back? Please stop with the math and cartoon thing where bugs shows daffy why gravity is not in effect around him. So you are saying that on a Alco style roller rocker system, as the engine goes into a curve the frame is not raised up by the front truck? Is that what you are saying?

Are we talking past each other?

Having a bad day normally would just watch.

Clint

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Re: WEIGHTING A LOCOMOTIVE PART 2

Post by JKreider » Tue Jun 07, 2016 6:47 pm

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SP&S700
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Re: WEIGHTING A LOCOMOTIVE PART 2

Post by SP&S700 » Wed Jun 08, 2016 3:13 pm

Ok
I deserved this since I made a post. Please define "vertical magnitude". Most references are concerning velocity. As you tilt an object toward 90 degree load is on the lower end. But I'll settle for the fact that the engine/frame is raised going through a curve. The geometry of the apparatus doing the raising also puts force on the lead truck to center. So I believe we are saying the same thing just talking past one another.

So yes bugs can defy gravity I saw it on tv.

I'll see if I can spend more time on vectors!

Thanks

Clint

LSGOD
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Re: WEIGHTING A LOCOMOTIVE PART 2

Post by LSGOD » Wed Jun 08, 2016 7:28 pm

Well Pennington and Krieder have caused Don (my son) to lose interest in Chaski.

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Re: WEIGHTING A LOCOMOTIVE PART 2

Post by LSGOD » Wed Jun 08, 2016 8:26 pm

In the perfect world the spring rigging on our models would take care of any vertical variations in the track keeping the weight perfectly distributed. Unfortionately most club tracks are not graded perfectley and sometimes the spring rigging BOTTOMS on dips lifting weight off the drivers. Adding coil springs on the rear spring anchors on the trailing truck (as on later GS class engines) and adding a large coil spring above the lead truck bolster solved a lot of problems by increasing the overall spring travel allowing the drivers to follow the rail better. No special science here. Jim Krieder is a very good friend of mine. I discussed this with him this PM. He agrees with me. Neither one of us is new to live steam.

Ed

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Re: WEIGHTING A LOCOMOTIVE PART 2

Post by Harold_V » Thu Jun 09, 2016 4:41 am

LSGOD wrote:Well Pennington and Krieder have caused Don (my son) to lose interest in Chaski.
That's unfortunate. I hope he'll return, as the idea of airing issues such as this is exactly why this board is of value. Concepts should be posted so they can be reviewed by those with knowledge. That often results in bystanders gaining valuable information that they may not otherwise gain.

So long as readers are mannerly, they should be free to express their views, assuming they're legal and respectable, anyway! :lol:

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.

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