Piston rod failure of a NYC Niagara (Oct 1949)

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Posted by Miningman on Thursday, November 22, 2018 5:05 PM

Good information. Have noticed you refer to the C1a on numerous occasions in several different threads. Too bad a prototype or a small run of them did not happen. Have to assume it was pretty darn close. 

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Posted by MidlandMike on Thursday, November 22, 2018 10:12 PM

Overmod
...tandem rods.

I'm having a hard time trying to picture those.

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Posted by M636C on Thursday, November 22, 2018 10:59 PM

MidlandMike

 

 
Overmod
...tandem rods.

 

I'm having a hard time trying to picture those.

 

The rods were really in parallel rather than in tandem, thinking about the real meaning of the words. Tandem compounds had one cylinder in front of the other which is a correct use of the term.

Peter

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Posted by Overmod on Thursday, November 22, 2018 11:20 PM

M636C
The rods were really in parallel rather than in tandem, thinking about the real meaning of the words.

And it doesn't help that there are two different senses of 'tandem' applying to side-rod practice!  (Neither of these having anything to do with tandem compounds...)

The earlier approach, which I believe was first used in the 1920s, used a combination of fork-and-blade rods and concentric bushings to spread the effective thrust of the main rod between the main pin it worked on and another pin, usually the one in the following driver.

The type seen on the Niagara (and the original J configuration) has two parallel thin Timken rods sandwiching the big end of the main rod, passing back to sandwich a single rod at the following driver pin.  This puts all the thrust of the main in a straight line down three sets of drivers.  ("Tandem" here being two side-by-side, as if 'yoked', as opposed to two in line as on captain/stoker bicycles)

It is interesting to compare the rod layout of the original and 'revised' versions of the N&W J, which we discussed several years ago here.  That puts the big end completely outboard of the rod system, with only the valve eccentric crank further out. 

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Posted by Jones1945 on Friday, November 23, 2018 5:22 AM

Overmod

What happened, of course, was that the improved Niagara turned out to be most of the things the C1a intended, without the drawbacks and compromises that the duplex 'state of the art' then involved. 

Thank you, Overmod. I find this thread from 2005 created by forum member feltonhill, he provided even more background about "the sketch in Trains magazine", I think he implied a sketch of a NYC C1a in the Trains mag but I am not sure if it was the same sketch I posted.

NYC C1a for UP829

http://cs.trains.com/ctr/f/3/t/47236.aspx

"feltonhill : I located the book you referenced which had more info than the sketch in Trains mag. Thanks for the info! 

The drawing is dated 3/28/45. The Niagara test report was dated 7/3/48. Tests with 6023 were run 6/46 to 11/46. Tests with 5500 were run 6/47 to 11/47. As you can see, the tests were run after the C1a sketch was made. It was probably one of the considerations that came out of the design process for the Niagaras and Central's awareness of PRR's activity with the T1's. 

I have no "official" performance estimates for the C1a. I ran some of my own figures to see what if may have done. I assumed the same boiler as a standard Niagara, but with the increased 290 psi pressure noted on the sketch. 

In regular service, it would have been only a slight improvement over the Niagara as far as fuel and water economy is concerned. It would have had a higher DBHP output at speeds above 70 mph due to the improved steam distribution of four small cylinders. However, considering how conservatively the Niagaras were designed with respect to tractive effort and adhesion, the C1a would have been harder to handle under the usually-found variable rail conditions on most railroads. A pair of jointly controlled two axle engine sets is touchier than one directly controlled four axle engine. Baker valve gear may have helped because poppet valves could reduce back pressure to the point that there was little to help arrest a slip once it occurred (other than shutting the throttle and waiting until everything settled back down). IMO Central was wise not to bother with the C1a."

Speaking of wise, I would spend more time to study B&O's business strategies since the 1930s. Just try to be practical. Coffee

 


 

Regarding the 100mph thing......

 

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Posted by Jones1945 on Wednesday, December 19, 2018 7:48 PM

I am reading the book "Know Thy Niagaras" by Thomas R. Gerbracht. In page 53, it shows a report of “Delays Chargeable to Engine” for the month of October 1948, when delays of Niagaras totaled 254 minutes due to various reasons; with thirteen failures and nine cut-outs. 

The Niagaras were almost three years old at this time and had received Class 2 repairs in 1948 for boiler replacement and any other work required. Intensive use of these excellent engines caused excessive wear and tear, but there is no mention about this piston rod failure in the book.

I wonder if there was any other RRs 4-8-4s surpassed Niagaras' workload in terms of average monthly mileage!  The most interesting part of this book for me is the test result of  S2a #5500 and production Niagaras as well as operating data compared with N&W Class J.

A very informative book with a lot of clear photos. (Why is there not a single book about PRR's Duplexes? I wish I will see one in the future!)

Tags: Niagaras

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Posted by Miningman on Wednesday, December 19, 2018 7:58 PM

Jones-- Niagara.. you spelt it wrong 4 x ( Niagra) but correctly once. 

Not complaining just trying to help.

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Posted by Jones1945 on Wednesday, December 19, 2018 10:25 PM

Ohh.. my..... Vince, thank you very much for pointing it out! I wonder what I was thinking! NYCentral's things and I are never a good fit! Embarrassed 

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Posted by Miningman on Thursday, December 20, 2018 12:12 AM

Siri changes whole words on me all the time when I'm not looking. 

One can really screw up when texting, it can lead to disaster! 

Too bad about the New York Central thing .. it's the Water Level Route and You Can Sleep! 

The NYC is my #1 US road because we spent summers and other occasions on a family farm right along the Canada Southern right of way.

Let me tell you it was magnificient and magic. It was incredibly traumatic when the steam stopped. I detested the Diesels intensely but I still had the CPR and the CNR for another 5.5 years whistling away.

BUT... the Central's Hudsons, Mohawks and Mikes and those 2 teapots in St. Thomas were unmatched really. Mind you I was just a wee gaffer and they were very special to me. 

I can't believe it's all gone. Drives me nuts.

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Posted by Firelock76 on Thursday, December 20, 2018 8:59 AM

Yeah, change can drive you nuts, especially if you haven't been asked about it first!

I look at it this way, when I visit New Jersey and see that Hiram's Roadstand, the B&W Bakery, and the State Line Lookout Inn are still there, my unchanging constants in a changing age, then things aren't so bad.

My other constant used to be Hiway Hobby House on Route 17 in Ramsey NJ.  It's where I used to blow all my money before I met Lady Firestorm.  Whistling   It's been gone for a while now.  Hey, the owner wanted to retire and the kids didn't want to take over the business, so what are you gonna do?

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Posted by BaltACD on Thursday, December 20, 2018 10:32 AM

Jones1945

 

Regarding the 100mph thing......

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Posted by Overmod on Thursday, December 20, 2018 10:40 AM

Jones1945
Intensive use of these excellen[t] engines caused excessive wear and tear, but there is no mention about this piston-rod failure in the book.

[Note changes in the grammar.  Excellence is a noun, not an adjective, no matter what modern ninnies may try to claim.  "Wear and tear" is an expression that applies in the singular to any number of pieces of equipment.]

The piston-rod failure is ominous in not just one respect, if that is in fact the original failure causing the incident.  It is, for those who understand what they're looking at, a consequence not necessarily of an accidental breakage but of what may be a combination of detail-design and operating overstress that is not adequately covered by a factor of safety -- and although I did not see this implicitly before, is occurring at the 'opposite end' of the linkage producing main-pin failures (through different mechanisms of action).  If it were complicated by a tribology failure of either the piston itself or the rod gland, it is if anything still more ominous.  Note that even pulling the cylinder head and inspecting the head of the piston wouldn't have exposed a developing failure -- you'd actually have to unkey the piston rod, extract it from the cylinder, and Magnaflux (or otherwise NDT it) to see the problem.  That's more than a little reminiscent of the reason those Full Cushion trucks were abruptly withdrawn from interchange service ... and never returned.

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Posted by Jones1945 on Thursday, December 20, 2018 1:49 PM

Miningman

BUT... the Central's Hudsons, Mohawks and Mikes and those 2 teapots in St. Thomas were unmatched really. Mind you I was just a wee gaffer and they were very special to me. 

I can't believe it's all gone. Drives me nuts.

Central's Dreyfuss Hudsons and MILW's Class A and F7s were probably some of the most famous and timeless icons of the States, but these beautiful machines were either de-streamlined after WWII or replaced by the diesel in the early-1950s. Until today, you could still see a lot of comments on different social platforms asking why they were not preserved. 

Firelock76
My other constant used to be Hiway Hobby House on Route 17 in Ramsey NJ.  It's where I used to blow all my money before I met Lady Firestorm.  Whistling   It's been gone for a while now.  Hey, the owner wanted to retire and the kids didn't want to take over the business, so what are you gonna do?

The demise of the hobby shop happened since the 2000s in my city. There were dozens of larger hobby shops in my city but only less than 5 still in business today. : (

Overmod

[Note changes in the grammar.  Excellence is a noun, not an adjective, no matter what modern ninnies may try to claim.  "Wear and tear" is an expression that applies in the singular to any number of pieces of equipment.]

Thanks for that, Overmod. But is there an App for this? ( I am still trying to finish that email about the valve gear thing, grammatical mistakes in the email will be jaw-dropping...I think I need something like this: https://www.youtube.com/watch?v=6AOpomu9V6Q Idea

By the way, thank you BaltACD for the video. I am gonna searching for some nice pics of Route 66!

Jones Family Railroad Hobby YouTube Channel: 
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Posted by BaltACD on Thursday, December 20, 2018 2:03 PM

Jones1945
By the way, thank you BaltACD for the video. I am gonna searching for some nice pics of Route 66!

'Cars' is worth watching for its own sake.

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Posted by Firelock76 on Thursday, December 20, 2018 4:33 PM

Mr. Jones, what is  your city?  I looked at the "About Jones1945" section (WOW! It's spectacular!) but it doesn't say, so I am curious.

If you'd rather not say that's fine with me.

And hobby shops?  When we moved to the Richmond VA area in 1987 there were four of them here, only one remains, and that one's on it's second owner.  The others?  Just like Hiway Hobby House, retirements with no one to take up the business. 

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Posted by Jones1945 on Friday, December 21, 2018 6:38 PM

Thank you, Firelock76, I am flattered.:-P If there is a straight rail track connecting Chicago and the place I am living in, it would take her about 70 days (without a break) to reach my city. Smile, Wink & Grin

The Hiway Hobby House have a "memorial" facebook page: https://www.facebook.com/Hi-Way-Hobby-House-323300055276/

It is hard to believe some of those pics were taken 40 years ago...

Jones Family Railroad Hobby YouTube Channel: 
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Posted by Overmod on Saturday, December 22, 2018 8:53 AM

Jones1945
It is hard to believe some of those pics were taken 40 years ago...

Harder still is to realize after watching the film clip that I clearly remember being in the OLD store, as if it were yesterday, and now even the new one is gone.

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Posted by Overmod on Saturday, December 22, 2018 9:01 AM

Jones1945
is there an App for this? ( I am still trying to finish that email about the valve gear thing, grammatical mistakes in the email will be jaw-dropping...I think I need something like this: https://www.youtube.com/watch?v=6AOpomu9V6Q

Hey, Smith could fly it! 

But seriously, there are a couple of apps that do seem to do 'grammar' properly, the one coming to mind quickly being "Grammarly" (which appeals to me for the way in which it was packaged and promoted, as well as its apparent operation).  I don't use it, but I would have to suspect it contains the ability to have technical material and perhaps even 'jargon' incorporated into it (perhaps as the old dictionaries in the original Microsoft Word for the Mac allowed) so that the things the program selects are appropriate even for abstruse things like valve-gear discussion.

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Posted by Firelock76 on Saturday, December 22, 2018 12:58 PM

Overmod, if there was anyone besides myself on this site who remembered Hiway Hobby I was sure it would be you!

And thanks for that Hiway Hobby link Mr. Jones!  I'm going to pass it along to the crowd in the "Classic Toy Trains" Forum and see if anyone there remembers it as well.

Hmmm, a straight line out of Chicago and then 70 days to get where you're at?  Sounds like you're a long  way from  Chicago or it's a one-way trip around the world to get home again!

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Posted by Jones1945 on Saturday, December 22, 2018 6:48 PM

Overmod

Hey, Smith could fly it! 

I am using the "Grammarly" already. But I am waiting for something, maybe a programme or device which is controlled by advanced AI smarter than chess engine Zor which could teach me everything like flying a Platt-LePage XR-1 or how to be a steam train engineer and fireman in 5 secs, like what Carrie-Anne Moss did in the movie. But if Elon Musk's world view is not a theory but the fact, it will only happen if it is written in the script. 

Firelock76

And thanks for that Hiway Hobby link Mr. Jones!  I'm going to pass it along to the crowd in the "Classic Toy Trains" Forum and see if anyone there remembers it as well.

Hmmm, a straight line out of Chicago and then 70 days to get where you're at?  Sounds like you're a long  way from  Chicago or it's a one-way trip around the world to get home again!

You are welcome, Firelock76. Those pics of Hiway Hobby also brought back the memory of me shopping in this kind of huge Hobby Shop. Those blue tint high color temperature fluorescent tubes in the shop was an icon of the 1970s to late 1980s. I love your one-way trip idea and I wish my S1 take me to the utopia at lightspeed instead of coming back to the earth. :- )

Let her spread the wings, Mr. Overmod and Firelock76!

 

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https://www.youtube.com/channel/UCu9gt9Q9RF-Hwq7xWciVcWg/

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Posted by M636C on Saturday, December 22, 2018 7:13 PM

Jones1945
 

 

Let her spread the wings Mr. Overmod and Firelock76!

I think that this is a Nord locomotive.

All of the PO Chapelon rebuilds were generally similar, but the junction of the footplate and the buffer beam varied. I think only the Nord locomotives had this version....

Peter

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Posted by Firelock76 on Saturday, December 22, 2018 8:35 PM

Gents, I just noticed something in the photograph that started this whole thread.

That piston rod laying on the ground.  Is that thing hollow?

I would have thought a component that would be subject to the kind of stresses a piston rod would be subjected to would be solid steel, not hollow like a water pipe.

Is that why it broke?

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Posted by Jones1945 on Saturday, December 22, 2018 9:36 PM

M636C

I think that this is a Nord locomotive.

All of the PO Chapelon rebuilds were generally similar, but the junction of the footplate and the buffer beam varied. I think only the Nord locomotives had this version....

Peter

I think you are right, Peter. They were some decent 4 cylinders engines with a TE of 45500lbs! no mechanical stokers so the fireman needed to work much harder. 

Firelock76

Gents, I just noticed something in the photograph that started this whole thread.

That piston rod laying on the ground.  Is that thing hollow?

I would have thought a component that would be subject to the kind of stresses a piston rod would be subjected to would be solid steel, not hollow like a water pipe.

Is that why it broke?

There is no mention of this kind of incident in the book of "Know thy Niagaras" and some long assay available on the web. I found no details let alone the reason. But I think a mechanical engineering expert like Overmod could give you a professional analyze about this incident. I seldom heard about problems of the Niagaras except for their firebox. :- )

Jones Family Railroad Hobby YouTube Channel: 
https://www.youtube.com/channel/UCu9gt9Q9RF-Hwq7xWciVcWg/

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Posted by daveklepper on Sunday, December 23, 2018 4:04 AM

For a given cross-section, a solid girder is stronger than a hollow gider; and for a given diameter, a solid piston is stronger than a hollow piston.  For a given weight of steel, a hollow girder is stronger than a solid girder; and, for a given weight of steel, a hollow piston is sronger than a solid piston.  The hollow girder has a larger cross-section than the solid girder, and the hollow piston a larger diameter than the solid piston.

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Posted by Overmod on Sunday, December 23, 2018 12:54 PM

Firelock76
That piston rod laying on the ground. Is that thing hollow?

Of course it is!  Read that 100mph Timken rod paper so kindly provided in the other thread -- it will tell you much of the theory behind the 'revolution' in high-speed balancing that took us from the ACL R1 to the NYC S1 in less than a decade.

You see here a possible overlooked problem in the detail design, the connection between the piston and the piston rod with a very lightweight and highly-dished piston.  All the peak thrust goes through the annular section of the piston rod, it is highly heated by superheated steam, the stresses reverse in sign every half revolution, and any incipient failure of the piston fit will rapidly start to 'work' (with somewhat ominous rapid development of failure if the piston starts to cock or jam in the bore...)

The situation is not quite the same for piston rods, which are loaded axially, as it is for axles or other rotated parts like the shafts in some Australian locomotives with conjugated 3-cylinder valve gear.  There, making the shafts hollow actually increases their effective strength to failure as well as reducing unsprung mass.  One of the saddest stillborn innovations in very late modern steam was the application of centrifugal casting to locomotive driver axles ... which I have been told firsthand was 'pitched' to locomotive shops in the Fifties, but by then nobody really still cared...

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Posted by Firelock76 on Sunday, December 23, 2018 5:03 PM

OK, that all makes sense.  Thanks!

By the way, I saw a hollow (dished) piston in operation today.  Lady Firestorm was making Christmas cookies with her Mirro cookie press.  Yep, hollow piston in that thing!

As Lady F says, "Only REAL women know how to handle a Mirro cookie press!"

They came out good too!

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