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The Most Suitable (non-mallet) Compound for U.S. Use

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Posted by Juniatha on Friday, February 26, 2021 12:11 AM

Ehr-hm, hi!


One more word on the three-cylinder engine:
I am no supporter of that engine when arranged as a compound. As a three-cylinder simple with 3 x 120° it alright and has its place and purpose. Still, that engine is not without some critical points in itself that have hardly been taken care of in regular steam times - for one: although the cylinders are significantly smaller than those of a comparable two-cylinder engine, frame demands are not easier but just different, loads are hardly diminished - why? because of the degree of cranking which provides a more counteracting work of the cylinders and since the frames are between the outside cylinders contortion of the frames is an important thing to take care of and look at from different angles. In that direction also go aspects of counterbalancing and cross balancing.

Side remark: I do not think this 'Eastern European' evaluation on the 05 was correct. Mind that A Wolff was one of the few engineers who took care looking into those matters, also the 05 were such 'long legged', if I may say so, engines that a typical proper frequency must if anything have been at lower, not higher rpm than with the smaller 01-10 / 03-10 three-cylinder engines of the same type of engine layout. For the 01-10, I know they had a peak of proper frequencies (a locomotive is not ideally stiff and therefore develops more than just one proper frequency) around 105 (worn engine) - 110 km/h - that relates to 279 - 292 rpm - way lower than the 05 ran at 200 km/h: 462 rpm. The smaller cylinders in the larger engine also contributed to keeping proper frequency at a rather low level. Indirect prove of this thesis came with the 18 201 that had larger cylinders than even the 01-10: 520 x 660 vs 500 x 660 mm. What made the situation worse was that the frames were lighter than those of both the 05 and the 01-10 since they stemmed from the original 61 002 a 4-6-6 three-cylinder tank engine of 390 x 660 mm cylinders. The rebuilt Pacific did develop a phenomenon of proper frequencies around 182 km/h that grew scary and demanded the cutting of the high-speed test. With the 05 no proper frequency phenomenon was to my knowledge experienced. If I estimate lower proper frequencies of the 05 relative to that of the shorter 01-10 as around 260 rpm, then the upper one would be around 520 rpm - relating to 225 km/h and thus still out of the way at 200 - 215 .. 217 km/h. From that point of view, the 05 had plenty of margin to surpass 200 km/h significantly.

I believe the point was as always with DR: you want to reach goals - but you never surpass them excessively. The goal originally was 150 km/h, quickly raised to 160 km/h the speed of the 'Flying' series railcars, finally raised to 175 km/h where it stayed. That speed had been fixed during the stage of collecting builder's proposals, long before the 'down fall' run of Mallard till hard against fatal destruction of the inner drive. No joke: destruction was already in progress: that was a typical British 'Sir Francis Drake' effort, or say it with Shakespear: it was to be or not to be! The Germans would be hard pressed to agree to such a risky all-out action. Also, mind that the reichsverkehrs-minister Julius Dorpmüller had accompanied the test run in the measuring car and his protection was above any wishes to allow a little 'piercing the unknown'. Still, the amount of 3400 ihp noted for 05 002 at the record run was way out of capacity for Mallard, whatever hard-driven, and given the importance of wind resistance at that speed range, this alone clearly indicates the 05 as the faster engine in the end.

Final recognition of what would happen in an all-out effort and what speed could be attained we could only learn if we took the engine out of the museum, undertake a complete revision, possibly equip her with DB given oil firing and have a go on modern high-speed track. As enlightening it would be, needless to mention this is as sure never to happen! Rests my remark that Mallard would not have come anywhere near to the 200 km/h mark without the help of the negative incline, not to mention slower acceleration might have caused unsustainable conditions to have developed already while at slower speeds than attainable by power output reached.

And now I haven't even mentioned the crocked curve of tractive effort development in a compound three-cylindder engine - and that applies to both the 3 x 120° and the 90 / 135° variation, only at differing work points.

Now, that could create extra and higher value proper frequencies!

Look at it from any viewpoint: the best of the compounds remains the four-cylinder type and in that the one with LP cylinders inside.

Juniatha

 

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Posted by Overmod on Friday, February 26, 2021 7:09 AM

Juniatha
With the 05 no proper frequency phenomenon was to my knowledge experienced. if I estimate lower proper frequencies of the 05 relative to that of the shorter 01-10 as around 260 rpm, then the upper one would be around 520 rpm - relative to 225 km/h and thus still out of the way at 200 - 215 .. 217 km/h.

Students at the University of Stuttgart did a SIMPACK simulation of the class 05 (discussed in SIMPACK News in June 2009) that supports this.  They found the onset of 'hunting instability' did not occur below 260km/h (and the kinematic oscillation was interesting at that speed, reaching a resonant peak at around 8s but becoming self-limiting at slightly reduced amplitude -- I am looking for a version of the graph I can reference here).

Interestingly, they identified a running instability in the tender around 225km/h, but reasoned (correctly, I think) that its coupling to the locomotive would keep any effect suppressed below 260km/h when the other effect developed.

 

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Posted by Sara T on Monday, March 1, 2021 9:56 AM

Overmod,

I, 05003, was never involved in these hasty runs. Before WWII I was in a ... I was .. hm .. you know .. not quite disposed, so to say.

In 1945 when I was at last put right, the times were horrifying and I did only run some 500 km then was shelved aside around Hamburg.

Then a British railway officer discovered me and ordered me to be put in running order. Then followed my best time - but circumstances were not for me. It only lasted two years and I was shelved aside again. 

Then came the Bundesbahn years, all three of us were overhauled at Maffei in Munich, but our boiler pressure was lowered to the usual 16 kp/cm² - much too low for us with the small cylinders! We were weakened, it hurt! That again only lasted a few years and DB lost interest and we were shelved for final this time. 

Noone came, none was rescued, we all went to the torch.

That was our rather dismal life.

0S5A0R0A3

 

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Posted by Overmod on Monday, March 1, 2021 11:15 AM

Sara T
Noone came, none was rescued, we all went to the torch.

Well, one of your sisters didn't, and the shop forces at Nuremberg worked carefully to put her back as intended... 

I DO still think some version of the cab-forward firing could have been made to work.  Whether that would be compatible with highest-speed running... I will not say.

Personally I'm still aghast Nelson Blount, who thought enough to preserve a runnable Schools-class 4-4-0, didn't save one of the 05s.  Scrapping them was (and is) like scrapping GG1s... better not imagined if you can avoid it!

One of the great collective American crimes was letting the Roosen motor locomotive we 'stole' be expediently scrapped for the Korean War.  Yes, I know we tried to send it back and nobody wanted it; I know there was never enough expressed interest in it here... but that was an important experiment in locomotive history, one difficult and perhaps impossible to re-create effectively today.  After the criminal liability of scrapping PRR 6100 I think this ranked second...

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Posted by Flintlock76 on Monday, March 1, 2021 3:23 PM

Overmod
 After the criminal liability of scrapping PRR 6100 I think this ranked second...

To say nothing of the PRR's scrapping of the S1 and ALL the T1's.

I mean really, the over-the-top Art Deco styling should have saved the S1 at least!

Well you know what they say:

"Don't cry because it's over, smile because it happened!"

https://www.youtube.com/watch?v=f-0-Ex6LH2g  

 

 

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Posted by Sara T on Tuesday, March 2, 2021 8:15 AM

>>Well, one of your sisters didn't, and the shop forces at Nuremberg worked carefully to put her back as intended... <<

 

Oh, yes, you are correct, Sina (002)! I didn't feel it because she sits in a house dead.  But I should of course have known from the museum. Sabine (001) was scrapped. Believe it or not I haven't been in the DB Museum at Nürnberg. Nor have I been at the steam shed they had or have (?) in Nürnberg. It does not interest me, it is all dead and cold.

0S5A0R0A3

 

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Posted by Juniatha on Tuesday, March 23, 2021 12:41 AM

Sara,

back in the first years after the 150 years celebration the steam shed in the regular depot at Nürnberg (not Nooriambeerge or the like, guys) was nice: the steam engines I saw at the age of ten were bright and clean and this made my picture of what the engines should look like; when I later saw S8 films of how they were at the end of regular steam times it was almost a shock to me: so run down, generally needing and all covered in soot and dirt, leaky, oily and rusty all at the same time, with dents and primitive makeshift repairs, even front number plates leaning, not horizontal - and the crews that worked on them like fresh from the garbage collection and chimney service, not even the faces were clean! Also, if you listened to a 44 class three cylinder engine start out with a freight and all you heard was whoom-fffham-thhh-wo-wowoo ... and with steam coming from you don't believe everywhere. Or the 012 Pacifics from Hamburg on the Westerland line: some with a leftside 'spinnaker' of steam as big as the exhaust above the chimney (from steam pipe forking left outside / inside cylinder) ... it was sickening sometimes, I got up and left to go out!

=J=

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Posted by Flintlock76 on Tuesday, March 23, 2021 9:07 AM

Juni, that sounds a lot like what happened here in the US in a number of places, that is, just do enough maintanance on the steamer to keep it alive until the diesel replacement showed up, and maybe not even enough!

I'd think the motivation level of the steam shop guys wasn't too high either knowing their jobs were coming to an end.

 

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Posted by Overmod on Tuesday, March 23, 2021 9:39 AM

Flintlock76
just do enough maintenance on the steamer to keep it alive until the diesel replacement showed up, and maybe not even enough!

There was more.  One relatively unremarked thing about modern steam was that parts of it could deteriorate with horrifying speed if poorly maintained.  I was told that on Q2s in storage, the alloy boiler steel could rust through nearly the full plate thickness in about a year -- granted that might have been accelerated by industrial pollution where the engines were stored, but it is indicative.

The A-2-A Berkshires were stored upon retirement from active service on the P&LE (this being one service where diesel-electrics were indeed much better suited, that being recognized almost as the engines were being built).  NYC had enough respect for Kiefer and the design to transfer the locomotives to NYC System use around Indianapolis, where they would have been useful ... except that in the comparatively short time they had been stored, they were ruined beyond economic repair as far as reliable service was concerned.  (See the Polarowitz book on the locomotives for details.)  Much of their 'street cred' as unwanted dogs with a bad name apparently stems, more or less directly, from this problem.

Kelly at Strasburg called their initial ultrasonic NDT tester 'the death ray' because of how its use revealed so many serious defects that had gone blissfully unrealized.  Steam can be intolerant of negligence, tireless in finding weak points in structure, and deadly without warning.  It is not some buggy whip or telegraph technology from the obsolescent past for cosplayers to have fun with. But that may not be evident until a Gettysburg or a Mentor.

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Posted by Flintlock76 on Tuesday, March 23, 2021 11:07 AM

AND there's the 2-6-6-2 the Western Maryland Scenic purchased from the B&O Museum!  To use an old cowboy saying she was "Rode hard and put away wet!"

Another one that toward the end of it's service life just got enough TLC until it's diesel replacement was on the property. 

I can't help but think that if the WMS knew what they were getting into they'd have told the museum "No thanks!"

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Posted by Overmod on Tuesday, March 23, 2021 11:39 AM

Sara T
Oh, yes, you are correct, Sina (002)! I didn't feel it because she sits in a house dead.

Not dead, but sleeping.  The dwarves dressed her up at the end and she sleeps in her glass coffin waiting to be brought back to life when the right prince takes the initiative.  As I said on another forum, the most appropriate music that should be played at the restoration to operation should be the end of the Firebird Suite, when the world wakes up from frozen horror and the steel casts off its chains and starts to dance...

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Posted by Sara T on Tuesday, March 23, 2021 10:11 PM

Overmod. >>Not dead, but sleeping.  The dwarves dressed her up at the end and she sleeps in her glass coffin waiting to be brought back to life when the right prince takes the initiative<<

Nicely written.  Sleeping - (smile), no, dead. We all faded away on the outmost track in the yard at Hamm in the winter of '58.  I know you wrote 'sleeping' because you believe some congregation could bring her back to running order. But if that would happen so on a subtle level would a new soul come settle in her, these subtle things are difficult to explain, and I don't want to go deeper into it, see pm. In short this is why one loco that had been a reliable performer in regular work times, could be a lazy performer no matter how scrutinazingly checked or a vicious one in newly re-built time, like I heard of the re-built 03  2295 is (or was).     

0S5A0R0A3

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