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Simple expansion verses compound expansion steam locomotives

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Posted by Firelock76 on Saturday, September 15, 2012 3:15 PM

I KNOW the N&W hauled more than coal!  J-M-J!   Gimme a little credit here, would ya?  I LOVE the N&W and the "Holy Trinity"  of  steam.  Jeez!

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Posted by BigJim on Saturday, September 15, 2012 3:37 PM

Firelock76
I KNOW the N&W hauled more than coal!  J-M-J!   Gimme a little credit here, would ya?  I LOVE the N&W and the "Holy Trinity"  of  steam.  Jeez!


I wasn't raggin' on you.
Just stating the fact that there are many misconceptions out there that just don't seem to go away. Like, the UP Big Boy was the biggest and best loco ever made, et al.

.

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Posted by Firelock76 on Saturday, September 15, 2012 5:52 PM

You mean the Big Boy WASN'T the biggest and best loco ever made???  I'm crushed!  Crushed I tell you!

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Posted by Thomas 9011 on Sunday, September 16, 2012 11:43 PM

Ulrich

Maybe you could help me with this...why can't the steam, once its done its work in the cylinder, be routed back to the boiler for reheating instead of being disipated to the atmosphere? This would be a closed loop where the steam would be reheated and reused. So far I'm told that it would be impossible to get the low pressure used steam back into the boiler where the pressure is higher.

It wouldn't work because the boiler is a pressure vessel. Any steam leaving the boiler is going to lose pressure as it goes through the pipes. The pressure is highest right when it leaves the throttle valve. After that it is all downhill from there. By the time it leaves the cylinders it has lost much of it's pressure which is why mallets had to have a considerably larger piston for the second expansion cycle.

You simply couldn't put 90 psi of steam pressure back into a 200 psi boiler. You couldn't even put 200 psi into a 200 psi boiler. You would have to raise it to probably 205 or 210 psi to inject it into the boiler.

All this talk about steam sure makes me wonder what we would have seen if steam could have lived another 10 years or so. Was there ever a locomotive that was built that had a second steam locomotive behind it, which was only serving as a auxiliary boiler to supply steam to the primary locomotive? Has this ever been tried? You would need a steam pipe connecting the two locomotives but it would give you a unlimited steam supply as it would be basically two boilers providing steam for one locomotive.

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Posted by Juniatha on Monday, September 17, 2012 12:03 PM

>> I'm crushed!  Crushed I tell you! <<

Hi Firelock

Wait , wait , don't - just ask = J = !   To de-crush you :

Big Boy was the one locomotive type with the largest number of axles between couplers , i e engine plus tender , of any steam locomotive on earth , Mallet or single frame concept , namely 19 .   However 'he' wasn't the longest steamer between couplers - this was long tall Sally-One , PRR 6100 .  BB also wasn't the one with the heftiest down thrust on rails , that was the Lima 2-6-6-6 BigFoot , exactly the Virginian RR version which was a little heftier than the previously built Carbon&Oxide version .   As concerns applicable tractive effort it makes little difference in principle if you have - to simplify ! - 2 x 4 axles loaded at 30 tons each or 2 x 3 axles loaded at 40 tons each .  

Since the ALCO Boys scaled at some 32 tons while the Lima Virgins kept 'diet' just below 40 tons per driven axle , you might want to suggest the Boys could grind some extra effort onto ramp rails , yet the Virchesty Halleygenny had an extra stamina for speed with a long train running because of 'her' large and deep firebox of unhampered proportions behind the drivers , rather than above them , which allowed to much better suit combustion .   Another question if Lima plain nozzle double chimney draughting was up to Jabelman's 2x4 nozzle double chimney design which again was far from perfect and certainly no match for an equivalent Kylchap design if properly executed .  

The longer articulated chassis didn't help the UP-Boys , at least not with conventional boiler design as it was then used in standard type steam locomotives in the US in the 1940s with basic decisions even such as between A type and E type superheater concepts still unresolved .   The earlier Triplex types should be considered as basically 2-8-8-0 with driven 0-8-2 or 0-8-4 tender and thus - other than for sheer total number of driven wheels - were not competitive for 'biggest'  just as they weren't output-wise .  The special series of 2-10-10-2s for the Virginian were formidable ramp roamers , yet again would just count for number of driven axles , neither for output nor speed nor length nor total number of axles between couplers .   Neither did the Y-6 .   Why not ?  Output was not high in comparison to engine mass since tractive effort collapsed pretty progressively as speed rose .    The Y at 63 mph ?   Thanx , I wouldn't want to have it !    Because of use of compounding ?   Yes and no - rather because of limitations of concept and design in the engine as realized than by principle of expansion .   

André Chapelon rode the cab of one on his visit to US railroads in 1938 and wrote quite appreciating of the engine .   Yet , when he calculated output reached on this regular trip over rising grades figures showed to have been comparatively moderate , speed readings on ramps were generally very slow and pretty moderate even on the level .   The Ys were really heavy grade climbers , not tonnage rollers - that was where the A class came in .    Chapelon was an integral gentleman who was positively prepared to appreciate other engineer's achievements and that's how he reported on his voyage to American RRs .   Remarkable , how in his following designs he integrated a number of major American design features , such as one piece engine bed ( in this case as a fully welded construction ) combining the best from both sides of the Atlantic to compose a new design quality of advanced and versatile steam locomotive .  

The 'North-Western' folks , as I like to call them , at Roanoke knew what to ask of their steam locomotives and they knew how to realize it .   They had a concise concept of design and an efficient organization of steam traction - that's why alleged diesel economies could not be realized as advertised by comparison of Old Steam against Modern Diesel as then invariably hammered down by EMD sales dept - slogan which , although of inherently ill logics , has since become petrified and ever repeated .   In fact , when N&W were about to become the only one RR retaining steam , they had a film produced to explain how those 'diesel advantages' were already realized by their three major steam classes , the J , the A and the Y-6 in combination with the way they were run .

However , admittedly , diesels still could be regarded much more economic if you only looked at it the right way :   basically , they didn't use steam - and for RRs like the Santa Fe that *was* a ponderous argument !

Don't worry - be happy !

Regards

Juniatha


P.S.: side remark :  I wonder what if Roanoke shops had decided to swap to motor cycle construction - Harley Davidson might as well have closed down ?   Just listen what a name for a Big Bike , if you let it roll off your tongue :

Have a ride on your Rrroanoke !

*gee* 


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Posted by CHUFF on Monday, September 17, 2012 9:47 PM

If you routed the spent steam back to the boiler, then how would you maintain draft thru the flues?  A problem with steam locomotives was that you had to expend that final bit of energy forcing the flue gases thru the petticoat and up the stack, where, of course, it's gone.  The exception was with the condensing engines used in South Africa and other desert climes - but then, how do THEY work?

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Posted by CHUFF on Monday, September 17, 2012 10:22 PM

Dear Juniatha:

  Dear, you might consider a tad less stylized writing; it gets a bit murky sometimes.  But charming.

  As for the N & W's steam program, if you look it "deep in the eyes", you really DO find that the diesel's advantages are, [alas!] overwhelming.  But let me add another, seldom mentioned reason to dieselize: 

  If you were a successful steam-powered railroad who wanted to expand your territory by buying a small but equally successful regional railroad, if you went to your financial backers to secure the funds necessary for the transaction, then might they not demand COLLATERAL for their financial aid??  And what can you offer as collateral - a clutch of steam engines, along with immoveable coaling towers and water cranes, plus machine facilities tailored to maintenance of steam engines?

  WHAT THE HELL GOOD IS THAT if you default on your loan, and you have to break up the railroad?  What are all the other railroads, who have already dieselised, going to do with your steam-powered assets?

  Face it, your little toy steam engines, no matter how efficient, are WORTHLESS to anyone but YOU. 

  And so, if you want to be a "player", you have to KEEP UP - if everyone else dieselizes, the YOU must dieselize - unless you wish to have your motive power assets regarded as quaint and worthless.

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Posted by seppburgh2 on Monday, September 17, 2012 10:25 PM

For those who feel the need for steam, the book N & W: The Giant of Steam, By Colonel Lewis Ingles Jeffries, ISBN-10: 087108547X, goes into the details of simple vs. compound on the N&W.  The Colonel does a great deep dive into what drove the N & W to invest not only in the hardware, but also the support systems with clear economic goals in mind.  Such as reduced water and coal stops on the main-line, getting 100% availability of a 0-8-0 switcher per shift without having to stop for either.  The only down size of the book is to so little was saved, such as the last built steamer (an 0-8-0) or a class Y for the future generations to see what magic art Roanoke made out of steel. 

 

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Posted by Deggesty on Monday, September 17, 2012 10:47 PM

CHUFF!

If you routed the spent steam back to the boiler, then how would you maintain draft thru the flues?  A problem with steam locomotives was that you had to expend that final bit of energy forcing the flue gases thru the petticoat and up the stack, where, of course, it's gone.  The exception was with the condensing engines used in South Africa and other desert climes - but then, how do THEY work?

How do you maintain the draft on a condensing locomotive? With the blower, which then runs all the time, and not just to get steam up before you begin moving. Hmm--if the blower is powered by steam, is its exhaust directed through the smokebox?

Johnny

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Posted by CSSHEGEWISCH on Tuesday, September 18, 2012 6:50 AM

Let's not give Roanoke too much credit for the S-1's, which were a C&O design.  C&O took delivery of 30 of the 0-8-0's just before the decision to dieselize and then sold them to N&W and VGN.  They wound up being N&W's first modern steam switcher and Roanoke built several additional batches to upgrade their yard service.

The daily commute is part of everyday life but I get two rides a day out of it. Paul
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Posted by Juniatha on Tuesday, September 18, 2012 12:52 PM

>> How do you maintain the draft on a condensing locomotive? With the blower, which then runs all the time, and not just to get steam up before you begin moving.<<


     Uhm .. not really , actually .  They had a blower instead and at the place of conventional draughting , run by exhaust steam turbine , before steam was directed backwards to the condensors - which again had steam turbine driven blowers for air re-cooling the condensers .

They also had a char ejector to be used according to char build up in the smokebox , mind SAR steam had self cleaning MM front ends . 

The sound of these engines was completely different from regular steam , more like a nest of wild African hornets in a ( smoke ) box - or like a grinding machine , as the blower got worn down , which it did progressively ( shades of UP pulverized coal turbine nuts ) .

Blower wear was one of the unresolved design problems of condensing steam locomotives , the other was sheer size and extra energy consumption of condensors .

Unfortunately , it appears no-one ever tried condensing in combination with oil-firing , only which would have set condi steam locomotives fully free of their traditional relatively short range of continuous running ( without stop to replenish supplies or handle fire ) 

It was different in Siberia in winter :  there it would have been sufficient to just exhaust steam while running and re-collect it in form of snow flakes by a large sail erected above an open tender - *gee* - however nobody cared , they just dumped the snow along the line , there was enough of it anyways . 

Just kidding ..

With regards

= J =

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Posted by Juniatha on Tuesday, September 18, 2012 1:03 PM

>> If you were a successful steam-powered railroad who wanted to expand your territory by buying a small but equally successful regional railroad, <<


     That's an original idea for selling diesels , I must say .

Still , if - as you suggest - I would have run that 'successful steam RR' in , say 1950 , and would want - if so , however I think I wouldn't want - to buy a 'successful regional diesel RR' I tell you what :  I'd just wait some years until that RR was bankrupt and then buy it for $ 1,-- and a bank guarantee granted on its ( probably pretty run down motive power ) so we get at least something out of it .

However , you're right , what you mentioned was done in fact , if somewhat differently :  steam locomotives got excluded from financing - that is : if you wanted them , you had to buy them cash , no credit no nothing .

That's when the builders had to give it up . 

In other words :   the diesel was so very efficient that it needed help by banking scene to get pushed .


Regards

= J =

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Posted by Firelock76 on Tuesday, September 18, 2012 7:59 PM

Hi Juniatha!  (I just came back from an eye exam, complete with dialating drops.  I've got a bad case of "Goo-goo eyes"  so if there's some spelling errors just bear with me!)   Thank you for "de-crushing"  me, I feel SO much better now!  I'm not so sure about Lady Firestorm though.  I've got a picture of her at the Dallas rail museum hanging on the pilot of a former UP 4000 with a "Hey Big Boy, new in town?"  look on her face.  She was very impressed with the Big Boy!

And I've said it before, I'll say it again, N&W  was rolling along just fat and happy with their magnificent steamers.  They did begin a slow dieselizing program on the branch lines first, retiring the old steamers, but kept the modern steam on the mainlines where it was still earning them money.  They just didn't see the need to rush, and they were probably right.  Remember we're talking about practical railroaders, not starry-eyed railfans.  Ah, I'm tired, I'll pick this up later.  Maybe.

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Posted by CHUFF on Tuesday, September 18, 2012 8:34 PM

 The hypothetical case I gave for a steam-powered RR dieselizing was of course a thinly-veiled account of Norfolk and Western's acquisition of the Nickel Plate.  The account I read several years ago was in an NRHS BULLETIN - forget the year or even the decade, but it was in the Burt Pennypacker era, and if Mr. P. was the one who wrote it, you can be sure it was well thought out and researched.

  The N&W handed off coal to the Pennsy to get its Pocahontas product to the Great Lakes, and the acquisition of the Nickel Plate would give it not only its own direct route to the Lakes but rails to Chicago, as well - a boon to an ambitious, expanding Railroad.

  Anyway, that's the story as I understand it, the operating officials must've realized by then that being a true Class I would require different operating procedures than being a little regional coal and merchandise hauler.  As that feller from Hibbing, Minn. would sing just a couple of years later:  "The Times, they are a'changin'"

  Final comment on blowers and I'll shut up.  Wouldn't the conventional method of exhausting the smoke up the stack be more efficient than using a blower?  I don't know what the engineering studies show, but "I'm just sayin".

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Posted by Juniatha on Wednesday, September 19, 2012 4:56 AM

Hi Firelock

Best wishes for your eyes recovery !   N&W :  you said it !

Hi Chuff

I see your point , yet sorry , I have to disagree Hmm .

I.

Dieselization of N&W was accomplished largely by applying pressure from interested parties in finance industry and by PRR who had part-ownership of N&W - in no ways it resulted by data collected of tested and proven relative technical efficiencies of traction modes .   N&W encountered an uncomfortable situation around 1950 .. 52 more determined by dieselized RR's not happy with N&W's profitable running when facing financial troubles with their immense investigations caused by actual total re-equippment of traction motive power and consequently finding themselves loaded with heavy interests to be paid to finance providers - again who didn't provide those credits to allow RRs to share the bliss of anything but just for mean profit making , at the costs of those RRs !  

II.

Practically *all* European RRs although with the virtually limitless financial backing of national traffic ministries found there was nothing to gain in hap-hazardly throwing away perfectly serviceable steam to buy power again only to do the same job - except for British Railways , maybe , they made a remarkable turn-around from steam building to steam scapping about 1962 / 63 .  

As late as 1965 the head of DB (German Federal Rys) traction dept turned down plans to acquire more V200 diesels on grounds they still had , off-hands quote from Duering , Die deutschen Einheits-Schnellzuglokomotiven , "enough fully serviceable and performing up to demands 01 class Pacifics available"  to do just the jobs for which those V200s were proposed to be bought .   Don't get me wrong :   dieselization was not turned down absolutely and forever , it was the way that was questioned and in due course facts have proven right those who opted for a more considerate action !

The same point had later been extended to the max with the three cylinder oil-fired 012 Pacifics which - although far from perfect in design - remained in service into the 1970s , finishing not before May 1975 and still in express service until their last days !  As late as 1970 Hamburg division found their 012 Pacifics did a better (!) overall job (on-time running , performance with train overloads , making up time , time keeping in adverse weather - there can be very severe winter snow storms on the northern flatlands) on the fast and heavy expresses on the mainlines to Westerland and Kiel than any diesel then in service on DB , namely 220 , 221 and 218 classes of 2200 , 2700 and 2500 nominal motor hp (the 012 was officially rated at 2500 ihp ;  according to my own calculation they should have been able to turn out some 3300 ihp max , this rating well conforming with notes of actual performance taken by some technically more educated guys who had seen these engines in action .   That said , mind these Pacifics , being on the way out , were in wanting and further deteriorating condition by 1970 - so much so that for their final years 1972 - 75 speed had to be limited to 75 mph because of mechanical deficiencies increasing .   The Hamburg div mainlines were dieselized by 218 class in autumn 1972 , with schedules lengthened , train consists being cut and services successively being thinned in later years until DBAG these days has 'succeeded' substantially to drop passenger miles . 

Principally the same relative performance was noted even later on East German DR comparing their 01.5 Pacifics with Co-Co russian built 132 class diesels of nominally 3000 motor hp !   Adversely as would reflect relative adhesion masses , the *heavier* (!) trains were scheduled to have 01.5 Pacifics - repetition of what had been practiced in the sixties on DB at Hannover shed with their un-rebuilt 01 / 220 diesels and at Kassel with 01.10 coal-fired Pacifics / 220 diesels over the ramps of Westerwald on the mainline to Frankfurt .   

     Nickel Plate was another RR that had tried for some time to resist dieselization and did not really follow to suit on basis of technical supremacy , just to keep it at that .   So if you had that RR in mind your example was not set up historically correct .   If you had the report on how PRR's dieselization was beeing decided upon that I have , you would probably be much more contemplative about these things .

III.

I don't claim copyrights on these considerations - perhaps considered heretical by some .  Before me , likewise comments had been offered by A Giesl (ÖBB) , A Chapelon (SNCF) , Roosen (Henschel) Th Duering (DB) , Marés (CSD) and others , later the case was carried on by L D Porta (Argentine Rys) and D Wardale (SAR) , LeSuer and others .  

Certainly , I do not agree with everything they wrote - only , there were / are a number of knowledgeable engineers who have found reasons to take exception from the beaten path of opinions and I have had a couple of thoughts on my own .

     Actually your comment can be regarded an example to my earlier statement on EMD selling slogans having been repeated until they have become regarded as quasi axioms accepted unquestioned  - or do you have actual figures of costs / revenues results of running certain modern (i e contemporary) steam in comparison to certain diesels on the same line in exactly the same service under identical conditions?  

Not even NYC had ever cared to put up that data on a strictly identical basis !   their often cited comparison of Niagaras with diesels was far from fully comparable if you take a closer look , just by the fact alone that diesel , to quote , "were given the optimum trains and Niagaras were given the next optimum trains left" - the former only taking new light weight streamline stock , the latter taking some further trains of this stock , the rest being made up of heavy weight conventional stock plus trains having more stops along the line in spite of heavier consists - which means it demanded power output clearly beyond the diesel's except for applying an absurd number of units .   As in this sort of service 'comparison' the Niagara still turned up service cost totals some 10% below three-unit diesel packs and higher only in comparison with clearly less powerful double-unit packs , then in fact the Niagaras should have won the case at hand if costs would have been related to gross revenues on a one-to-one basis , not on basis of trains run , regardless of consist and number of passengers transported .

Side remark , specially concerning N&W and their practical structure of train service :   what's the revenue in a diesel being 'available' a couple of extra percentages of total time if that time is made up of fractions of time spent on ready tracks in engine yards with the motor doodling 'ready-ready-ready-ready-ready-ready ..' for hours until the next scheduled train is due ?  Nothing - on the contrary , it just burns diesel fuel  that's all .   The like can be seen happening every day on British Rail Companies , SNCF , DB or any Eastern European national railways .   I think we'll agree this cannot really be considered an efficient way to run a railroad .

No insult intended , we may well agree to disagree and still remain at ease .

Regards

Juniatha

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Posted by wjstix on Wednesday, September 19, 2012 11:27 AM

Juniatha

     Actually your comment can be regarded an example to my earlier statement on EMD selling slogans having been repeated until they have become regarded as quasi axioms accepted unquestioned  - or do you have actual figures of costs / revenues results of running certain modern (i e contemporary) steam in comparison to certain diesels on the same line in exactly the same service under identical conditions?  

 
Great Northern c.1940 used steam on freight and passenger trains between Minneapolis-St.Paul and Duluth-Superior. An engine would pull a passenger train (Gopher or Badger) during the day, spend the night in the roundhouse, and return on a passenger train the next day. A similar schedule was used for freights, which often ran at night. Engines would take the freight train to one terminal one day, and return with a train the next day.
 
In 1941 when GN bought steam-boiler equipped A-B sets of FTs from GM, they soon found they could use them to haul a passenger train from the Twin Cities to the Twin Ports in the day, and the same A-B set could pull a freight train back to the Twin Cities that night. They could do a round trip every day, week after week, with just minor / routine maintenance. So in effect one diesel (an A-B set connected by a drawbar) replaced two steam engines (one passenger engine and one freight engine).
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Posted by K4sPRR on Wednesday, September 19, 2012 11:46 AM

Chuff's assessments were not totally off the mark.  The N&W avoided dieselization mainly to the fact that many railroads who did expedite dieselization were facing financial strains by doing such added to post war problems with railroads falling revenues.  The N&W was not pressured by the PRR or other financial factions to do such, they were simply protecting their bottom line which up to this point was quite impressive compared to other roads.  They chose to hold off and and avoid such mistakes and do such in a more prudent financial way.  (Source: N&W HS)

Why would the PRR jeopardize their holding in the N&W, at this time it was one of the few things keeping their finances afloat.

The PRR on average had 8.5 to 10 % of their coal revenues from shipping coal to other railroads for their steam locomotives.  As late as 1946 the PRR was still seriously contemplating building steam over dieselization.  The PRR and six other roads to include the N&W were still looking at ways to improve modern steam.  As to the diesel coming on board it was more a situation like ice placed in a boiling pot of water, the ice had no choice but to give in.  (Source: Black Gold, Black Diamonds, vol 1: PRRT&HS) 

The diesel was a hard sell to the N&W, like previously mentioned about the N&W making a film regarding steam versus the diesel, when it came to raw power at that time they had a legitimate arguement that steam was better.   If it were proven to them that it was a matter of economics maybe their attitude would have been different, but they were not convinced and they were doing just fine.

..."whats the revenue in a steam engine being available a couple of extra percentages of total time if that time is made up of fractions of time spent on ready tracks in engine yards with the locomotive doodling' ready...for hours until the next scheduled train is due?  Nothing...it just burns coal, thats all."  Moot.

I am sometimes amused at how the European countryside views American financing.  Our capitalistic ways seem wasteful at times and are overly criticized.  In the matter of steam to diesel, history has shown it was a trying decision and indicates how capitalism gives opportunity for the best solution, collectively and indivually, no matter what direction is taken.  Quoting European attitudes on this is somewhat biased and looked upon at times with jealous envy. 

Now, lets get back to the topic at hand.  If expended steam was reintroduced into the boiler by the force of the piston wouldn't that pressure be adequate to do such if it was pushed into the lower portion of the boiler?  I believe some experiments by American rails were done on this topic and there were no significant results to justify a change, and drafting problems also arose.  It is a shame that expended steam still has over 95% of its energy when flying out the stack (Source: Basic Locomotive Maintenance).  Such a capitalistic waste (opinion).  

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Posted by tdmidget on Wednesday, September 19, 2012 10:17 PM

"Now, lets get back to the topic at hand.  If expended steam was reintroduced into the boiler by the force of the piston wouldn't that pressure be adequate to do such if it was pushed into the lower portion of the boiler?  I believe some experiments by American rails were done on this topic and there were no significant results to justify a change, and drafting problems also arose.  It is a shame that expended steam still has over 95% of its energy when flying out the stack (Source: Basic Locomotive Maintenance).  Such a capitalistic waste (opinion).  "

Are you under the impression that the boiler pressure is lower at the bottom?

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Posted by Thomas 9011 on Wednesday, September 19, 2012 11:21 PM

Steam loses power and heat at a very fast rate. As a matter of fact it's pretty rare to see real steam. What you see coming out of the smoke stack of a locomotive is actually water vapor and not steam. If you ever see a safety valve open on a locomotive you might notice that there is a about 6 inches or so of empty space at the very top of the safety valve before you see the white plume of water vapor. That little space is real steam. The rest is just water vapor. That just goes to show you how fast steam cools off and that is right out of the steam dome.

Another good example is a steam locomotive with it's cylinder drain cocks open. Anyone who has ever stood beside a locomotive and been blasted by the cylinder cocks knows it is not hot it is cold.

I find the 95% not believable at all. Most steam locomotives have gauges called a "back pressure gauge" which measure the exhausting steam pressure on the cylinder heads. All the times I have rode  on steam locomotives and occasionally drove steam locomotives, that gauge was typically zero or less than 10 PSI for most of the time. When you were going up a grade the gauge would go way up to around 90 PSI but in any case it was far lower than the boiler pressure. But the PSI can be deceiving because the exhaust valve is open letting out the majority of the pressure.

The root of this problem is the fact that you have a boiler at 200 PSI. When you are working a steam locomotive on a level grade with a light train, you are not working the locomotive that hard. Hardly any steam is being used, yet steam is being used. If you are only using say 1/4 of the throttle it's fair to say you are probably using 50 PSI. 50 PSI will drop considerably by the time it goes through the pipes and through the cylinders so there is no way you are going to get 50 PSI back into a 200 PSI boiler.

It is possible to put 200 PSI back into a 200 PSI boiler using water and a injector. But water is a solid and does not compress and is easy to push. The injector also has a venturi tube which speeds things up considerably .Steam and Air can be compressed which complicates just about everything.

I am sure if steam could be pumped back into the boiler, all the powerhouses in America would be doing it. 

 

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Posted by K4sPRR on Thursday, September 20, 2012 7:52 AM

tdmidget

"Now, lets get back to the topic at hand.  If expended steam was reintroduced into the boiler by the force of the piston wouldn't that pressure be adequate to do such if it was pushed into the lower portion of the boiler?  I believe some experiments by American rails were done on this topic and there were no significant results to justify a change, and drafting problems also arose.  It is a shame that expended steam still has over 95% of its energy when flying out the stack (Source: Basic Locomotive Maintenance).  Such a capitalistic waste (opinion).  "

Are you under the impression that the boiler pressure is lower at the bottom?

tdmidget: Not less pressure but as with introduced water a syphoning effect. 

Thomas 9011, thanks for your explaination, clearly stated.  The 95%  I mentioned is not the PSI but the energy contained within the steam.  The book I referenced was a shop manual from the early 1900's and even then they expressed frustration that so much of steams energy is not harnessed.

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Posted by selector on Thursday, September 20, 2012 11:43 AM

To get reduced steam from a larger cylinder back into the boiler would require enough pressure per square inch to overcome the check valve admitting the steam into the boiler that at the same time did not allow steam to escape from that valve.  It would be akin to a perpetual motion device, and would defeat the purpose of the compounding in the first place.   You want the work from the large low pressure cylinders to be for motive force, not for forcing colder vapours back into the boiler. 

You would need a collection system for syphoning, or an injector or feedwater pump to get condensate, and not steam, back into the boiler.

At least, in my non-engineer mind, that is how it appears to me.

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Posted by Juniatha on Thursday, September 20, 2012 2:14 PM

@ wystix:

If they did that , for sure they didn't do that for very long - and absolutely certainly they didn't continue that misuse without having to pay the price .

What do you think why EMD turned out the same model as a passenger and as a freight unit ?  

Even with electric locomotives about four times more powerful per mass unit it has been a challenge to develop types equally suited for freight as for passenger traffic - and that only concerns European size of freight trains like say 1800 - 2400 t , not five digit tons trains of American pactice .   It took a Bo-Bo of 6000 kW to do that !    How does that compare to those early EMD units of 1350 hp , each one weighing about 1 1/2 times this electric ?   Diesels cannot compete with electric traction in performance - absolutely no way .

Look , that kind of 'lengendary' argumentation just does not provide any basis for a fair and fact-oriented discussion fruitful and informative for all participants .   My point of view is that of engineering where there is no space for legends , please mind that such things as t.e. / running resistances and ampacy are values subjected to physical laws and physics make no exception for anyone  - so let's drop it here .

Juniatha

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Posted by Juniatha on Thursday, September 20, 2012 2:49 PM

@ K4sPRR

>> It is a shame that expended steam still has over 95% of its energy when flying out the stack <<

Sorry , how do you mate that with the fact there were steam locomotives of 10 % and better overall efficiency ?

>> Our capitalistic ways seem wasteful at times <<

Your answer to my question :
"what's the revenue in a diesel being 'available' a couple of extra percentages of total time if that time is made up of fractions of time spent on ready tracks"
First , you misquoted me !  I did not write >> steam engine << , I wrote "diesel engine" !  I ask you not to invert my words , that's a poor way of argumentation !
Else , I conclude you agree in fact it is but a waste of fuel , however you define it as 'American capitalist way' .   Ok , only then I have to say , American railroads have since become quite 'Un-American' in this respect in that they try hard to save fuel wherever possible .   They are not , they have understood what present day economies ask of them and act consequently - that's American enterprise !   Twentieth century has passed us by and challenges are different and much more severe in present times , no dreaming or conjuring of former glory will help us to win the future !

By the way :  All of Europe is a as capitalistic as America ,  iron curtain has fallen over 20 years ago .   To be sure :  I live in Europe presently , yet I was born in America and I will always be American at heart .

Regards

Juniatha

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Posted by K4sPRR on Thursday, September 20, 2012 3:33 PM

The term steam locomotive was inserted instead of diesel on purpose, the result in your scenario is the same, therefore a moot point,  it was not argumentation as you mention but somewhat meaningless in your reply.  They were my words, not yours.

I did not state it as"American capitalist way"in the misinterpretation you present, I simply stated that most Europeans look at American's as wasteful.  I hear it all the time from relatives in Germany, and I agree, in many facets of our society, to include financial matters, we can be and are. 

Yes, I agree also that challenges are different, but many times when one goes to find himself, all he has to do is look into the rearview mirror.

Have a great one.    

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Posted by Juniatha on Thursday, September 20, 2012 4:02 PM

@ K4sPRR

>> They were my words, not yours. <<

Sorry , you put my words in quoatation marks and so it was a quotation .   ´They were not your words since all the rest of the sentence is identical with my words .  So don't twist arguments again , stand to your point !

>> the result in your scenario is the same <<

That shows you have not understood what I meant to say - likely , you don't want to see my point because it contradicts with views you have become acustomed to .

>> I simply stated that most Europeans look at American's as wasteful. <<

What does that have to do with the question what revenue can be squeezed out of extra availability or not ?

>> I hear it all the time from relatives in Germany ,, <<

I know all too well what contorted and mindboggling ideas and preoccupations many Germans have about America and 'the Americans' - not even knowing what widely differing members of our society we have .

I propose to end this herewith , the discussion leads nowhere .   You're free to keep your point of view as I am to keep mine - no insult intended .   As the British say :  we agree to disagree - and that's no problem at all .

Regards

Juniatha

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Posted by Ulrich on Thursday, September 20, 2012 5:19 PM

selector

To get reduced steam from a larger cylinder back into the boiler would require enough pressure per square inch to overcome the check valve admitting the steam into the boiler that at the same time did not allow steam to escape from that valve.  It would be akin to a perpetual motion device, and would defeat the purpose of the compounding in the first place.   You want the work from the large low pressure cylinders to be for motive force, not for forcing colder vapours back into the boiler. 

You would need a collection system for syphoning, or an injector or feedwater pump to get condensate, and not steam, back into the boiler.

At least, in my non-engineer mind, that is how it appears to me.

 

My idea has been shot down, but it wouldn't be a perpetual motion machine. However,  you are correct..the energy expended in getting the used steam back into the boiler would be too great and would render my idea impractical. Oh well...no great technological breakthrough but at least I learned something.  

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Posted by AnthonyV on Thursday, September 20, 2012 6:45 PM

Ulrich

selector

To get reduced steam from a larger cylinder back into the boiler would require enough pressure per square inch to overcome the check valve admitting the steam into the boiler that at the same time did not allow steam to escape from that valve.  It would be akin to a perpetual motion device, and would defeat the purpose of the compounding in the first place.   You want the work from the large low pressure cylinders to be for motive force, not for forcing colder vapours back into the boiler. 

You would need a collection system for syphoning, or an injector or feedwater pump to get condensate, and not steam, back into the boiler.

At least, in my non-engineer mind, that is how it appears to me.

 

My idea has been shot down, but it wouldn't be a perpetual motion machine. However,  you are correct..the energy expended in getting the used steam back into the boiler would be too great and would render my idea impractical. Oh well...no great technological breakthrough but at least I learned something.  

Ulrich:

While the practical considerations noted by others are important, a machine that operates by compressing steam, reheating the steam, and expanding the steam over and over again is impossible.

Such a machine would deliver net work while operating in a cycle and exchanging heat with only one reservoir.  This is called a perpetual motion machine of the second kind and would violate the laws of thermodynamics.

Heat engines must interact with high and lower temperature reservoirs, which means that they must reject heat to a low temperature sink.  Thermodynamic laws dictate that for a heat engine operating at typical steam engine operating conditions, at least 75 percent of the heat added in the boiler must be rejected to the atmosphere, regardless whether the working fluid condenses or not.  This number is even higher when system ineffeciencies are included.

Anthony V,

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Posted by Firelock76 on Thursday, September 20, 2012 7:11 PM

Wow, I would give ANYTHING  (OK, not "anything", but you get the picture)  to have us all sitting around a coal stove in the  "Ol' Depot"  with some coffee and doughnuts carrying on this discussion!  I LOVE this stuff!

Juniatha, you GO girl!  Thanks for butressing my contention the Europeans knew what they were doing when they didn't rush headlong into dieselization.  Oh, and the aforementioned Nickle Plate?  They ran steam until 1958, just about the time N&W was looking them over for purchase.

Now at the risk of offending the Pennsy fans out there, if the Pennsy heirarchy was so savvy, WHY did they sell off their shares of the N&W?  N&W was a guaranteed money-maker for the PRR, all Pennsy had to do was sit back and count the money coming in.  Have any of you read Rush Loving's  "The Men Who Loved Trains"?  I'm sure a lot of you have, but if you haven't find a copy and read it, it's an eye-opener.  The men running the PRR around 1960 or so weren't as smart as they thought they were, or maybe they were too smart for their own good.

Mind you, I'm not doctrinaire on this, I realize some roads dieselized for very, very good reasons.  My favorite, the Jersey Central, hadn't bought a new steam engine since 1930 and by 1945 the ones they had were wearing out.  They needed new power so they went with diesels. For 'roads in arid parts of the country where water was a problem diesels made sense.  For 'roads in parts of the country where there was no coal and the steamers had to burn oil diesels made sense.  If you're going to burn oil you may as well do it in the most efficient manner possible.  For the 'roads in upper New England where there was no coal OR oil it was a lot easier to ship in oil fuel than coal.  Even the "Anthracite Roads"  went diesel, they didn't burn what they hauled anymore, modern steam couldn't use waste anthracite like the old "Camelbacks"  did, they had to ship in bituminous coal for fuel.

Anyway, as a student of history  I look at past events with the idea of  "What can we learn from this?  Were mistakes made, and if they were how do we avoid making the same mistakes again?"   In my mind, sometimes it's not such a good thing to go totally "ga-ga"  over a new technology until it's more than proven itself.  I look at people going berserk over the latest electronic gadgets and applications both large and small and can't help but think we're heading for a "Digital Titanic".  Think it won't happen?  Just you wait.

Anyway, the slow approach by the N&W was the right approach, and probably for a few other roads as well.  Then again, maybe it's just me wishing big steam held on until 1970!

By the way, slide over to the "Classic Trains Magazine"  'site and check out their "Forum".  There's a thread ongoing called  "Santa Fe not loyal to steam."   You might find it interesting.

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Posted by Thomas 9011 on Thursday, September 20, 2012 10:45 PM

One big problem and one that very few people ever talk about is how the supplier of locomotive parts plays in the big picture.I have worked for two amusement parks as a mechanic and when a ride breaks down you are at the mercy of the parts supplier which is typically the company that made the machine. It was a rarity if the company actually had the parts. A typical response was " we have three orders for this part number. When we get 10 orders we will make it again and send it to you". They explained that it was not profitable to make parts on demand because of resources and tooling, and instead only make them on 10 or more orders. This wait could take several years before enough orders are filled and we had some rides down for years because of this.

I think this was a major death blow for the steam locomotives. Are you going to keep a entire factory open for another 20 or so years to make spare parts for the steam locomotives still out there that are declining ever year? This could explain why the steam locomotives in the twilight years were typically parked and abandon when they needed major repairs. Perhaps they couldn't even get the parts they needed.

I have been a mechanic most of my life and spent a good portion of those years turning wrenches on locomotives and rail cars. I have learned as long as there is a parts source those old locomotives will keep chugging on for as long as possible. ALCO is long gone yet ALCO parts are in good supply. Is there any doubt had ALCO decided not to keep the spare parts flowing it would be the death of every ALCO locomotive on the rails or at least until the spare parts ran out.

  

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Posted by seppburgh2 on Friday, September 21, 2012 1:00 AM

Standard Stoker, where are you?

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