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Alleghenies

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Posted by kgbw49 on Friday, December 16, 2022 8:22 PM

Atlantic Central and sgriggs, great discussion!

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Posted by ATLANTIC CENTRAL on Friday, December 16, 2022 4:37 PM

sgriggs

 

 
ATLANTIC CENTRAL

 

 
sgriggs

 

 
ATLANTIC CENTRAL

 

 
kgbw49

In an alternate universe it would have been interesting to see how an Allegheny would have fared over Sherman Hill and the Wasatch Range.

I know, I know, different fuel, different builder allegiance, 110,000 lbs tractive effort instead of the Big Boy's 135,000 lbs tractive effort, 12 drivers instead of 16 drivers.

But 13% more tractive effort than a Challenger.

I am just saying it would have been interesting to see an Allegheny give Sherman Hill and the Wasatch Range a go where there was more fast freight opportuniity and a rugged test.

In an alternate universe.

 

 

 

I think an Allegheny could have replaced a Big Boy or Challenger out west with acceptable results.

But neither a Big Boy or an ALCO Challenger could have replaced the Allegheny, or the N&W Class A, in the east.

The Big Boy is not "nimble" enough for Appalachia, and as you point out, the Challenger lacks the power.

I think the C&O/LIMA and the N&W understood the "nimble" issue when staying with 12 drivers, and that is born out by the B&O experiances with EM-1's at higher speeds.

Sheldon

 

 

 

 

I don't agree with this at all.  The Alleghenies were terribly overweight and wouldn't have even been allowed on UP property with their 86,000lbs axle loadings (UP axle load limits during the late steam era were 68,000lbs).  In spite of their axle loadings, the Alleghenies were much less capable than the UP Big Boys in the service these locomotives were intended for.  On their railroads' respective 1.14% ruling grades, the Alleghenies were only rated for 2950 tons, whereas the Big Boys were initially rated for 3600 tons (later increased to as much as 4450 tons).  People like to focus on the maximum horsepower capabilities, but overlook the important performance differences in the speed range where these locomotives operated more frequently.  The Allegheny had 35,000lbs less weight on drivers, smaller cylinders, and lower boiler pressure, all of which are significant drawbacks for a locomotive intended to haul heavy trains on mountain grades.  As a result, the Big Boys developed more horsepower than the Allegheny up to 25mph, allowing faster acceleration from stops, and offsetting some of the Allegheny's horsepower advantage at higher speeds.

With respect to whether the Big Boy would have been nimble enough to handle mainline coal trains in C&O territory, they could negotiate 20 degree curves and were shorter in overall height than the Allegheny.  The only question would be whether clearances to adjacent tracks on the C&O mainline would permit their operation, however let's not forget that the Allegheny was itself a very large machine.

 

 

 

Well, you make a good point about the axle loading, east coast roads in general where built with heavier trackage.

As for the nimble thing, I am aware of the abilities of the BigBoy on curves, but locos with longer engine wheel bases cannot maintain higher speeds around sharper curves, loose TE faster on sharper curves, etc.

An over all examination of eastern power vs western powers shows this difference. 

Western roads had/have great "straight a ways" where their tall drivers locos could stretch their legs. And if they had to slow down for some curves in some mountains that was ok.

But in the east straight a ways are rare, every line, level or in the mountains, is one curve after another winding thru the soft hills of the piedmont or around other pre-existing or natural obstacles (Bays, rivers, existing cities, not to mention our smaller, but in some ways more challenging mountains).

So smaller drivers and shorter rigid wheel bases allow moderate speeds on more milage.

The B&O learned this lesson with their 2-10-2's. After dumping one over on the old mainline, they stayed on the straighter Pittsburgh route. The old mainline required the articulated locos, draging coal or cruising along with general merchandise.

The Big Boy was built for a job, it did it well. The Allegheny was built to be more versitile (because that is what LIMA was selling with "Super Power"), and its "supposed" mis-use possibly proves how versitile.

But I could be wrong.....

Sheldon 

 

 

 

Sheldon,

When you use the term 'engine wheel base' you seem to be referring to the rigid wheelbase of the each coupled driver set.  And while there is no disputing that a 6-coupled engine like the Allegheny or the class A has a shorter rigid wheelbase on each of the articulated engines than an 8-coupled engine like a Big Boy or Yellowstone, I don't know that such a difference has a meaningful effect on the locomotive's ability to maintain speeds or tractive effort on Eastern U.S. mountain railroad mainlines.  There are certainly examples of 8-coupled non-articulated locomotives that were successfully operated on mountainous mainlines in the Eastern U.S.  For example, the N&W J, the C&O Greenbriar, and the AMC 2-8-4 Berkshires all have rigid wheelbases roughly equal to the UP Big Boy, and none of them were considered poor performers in the mountains.  The B&O EM-1 was as close to a UP Big Boy as there was in the East, and they were very successful in all service assignments, including their initial work on the demanding Cumberland division hauling coal and fast freights. 

So I don't quite understand how a UP Big Boy would have been unable to put its low speed advantages to work on the C&O mainline, and outperform the Allegheny hauling coal its own rails.  I also don't see how the Allegheny could do a Big Boy's job on the Wahsatch, or Sherman Hill, since it lacked the starting TE to handle the Big Boy's tonnage ratings.  That is not my definition of being more versatile.

To my mind, the Allegheny was over-boilered for all but the heaviest fast freights, and its design was not suited for C&O's needs, which were hauling heavy coal trains over the Alleghany summit.  This should surprise no one, because the Allegheny wheel arrangement and primary design parameters were selected by the railroad parent company's Advisory Mechanical Committee, with little to no input from the C&O's traffic or mechanical departments.  This is documented in multiple books by Huddleston and Withuhn.  

Scott

 

OK

    

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Posted by sgriggs on Friday, December 16, 2022 4:12 PM

ATLANTIC CENTRAL

 

 
sgriggs

 

 
ATLANTIC CENTRAL

 

 
kgbw49

In an alternate universe it would have been interesting to see how an Allegheny would have fared over Sherman Hill and the Wasatch Range.

I know, I know, different fuel, different builder allegiance, 110,000 lbs tractive effort instead of the Big Boy's 135,000 lbs tractive effort, 12 drivers instead of 16 drivers.

But 13% more tractive effort than a Challenger.

I am just saying it would have been interesting to see an Allegheny give Sherman Hill and the Wasatch Range a go where there was more fast freight opportuniity and a rugged test.

In an alternate universe.

 

 

 

I think an Allegheny could have replaced a Big Boy or Challenger out west with acceptable results.

But neither a Big Boy or an ALCO Challenger could have replaced the Allegheny, or the N&W Class A, in the east.

The Big Boy is not "nimble" enough for Appalachia, and as you point out, the Challenger lacks the power.

I think the C&O/LIMA and the N&W understood the "nimble" issue when staying with 12 drivers, and that is born out by the B&O experiances with EM-1's at higher speeds.

Sheldon

 

 

 

 

I don't agree with this at all.  The Alleghenies were terribly overweight and wouldn't have even been allowed on UP property with their 86,000lbs axle loadings (UP axle load limits during the late steam era were 68,000lbs).  In spite of their axle loadings, the Alleghenies were much less capable than the UP Big Boys in the service these locomotives were intended for.  On their railroads' respective 1.14% ruling grades, the Alleghenies were only rated for 2950 tons, whereas the Big Boys were initially rated for 3600 tons (later increased to as much as 4450 tons).  People like to focus on the maximum horsepower capabilities, but overlook the important performance differences in the speed range where these locomotives operated more frequently.  The Allegheny had 35,000lbs less weight on drivers, smaller cylinders, and lower boiler pressure, all of which are significant drawbacks for a locomotive intended to haul heavy trains on mountain grades.  As a result, the Big Boys developed more horsepower than the Allegheny up to 25mph, allowing faster acceleration from stops, and offsetting some of the Allegheny's horsepower advantage at higher speeds.

With respect to whether the Big Boy would have been nimble enough to handle mainline coal trains in C&O territory, they could negotiate 20 degree curves and were shorter in overall height than the Allegheny.  The only question would be whether clearances to adjacent tracks on the C&O mainline would permit their operation, however let's not forget that the Allegheny was itself a very large machine.

 

 

 

Well, you make a good point about the axle loading, east coast roads in general where built with heavier trackage.

As for the nimble thing, I am aware of the abilities of the BigBoy on curves, but locos with longer engine wheel bases cannot maintain higher speeds around sharper curves, loose TE faster on sharper curves, etc.

An over all examination of eastern power vs western powers shows this difference. 

Western roads had/have great "straight a ways" where their tall drivers locos could stretch their legs. And if they had to slow down for some curves in some mountains that was ok.

But in the east straight a ways are rare, every line, level or in the mountains, is one curve after another winding thru the soft hills of the piedmont or around other pre-existing or natural obstacles (Bays, rivers, existing cities, not to mention our smaller, but in some ways more challenging mountains).

So smaller drivers and shorter rigid wheel bases allow moderate speeds on more milage.

The B&O learned this lesson with their 2-10-2's. After dumping one over on the old mainline, they stayed on the straighter Pittsburgh route. The old mainline required the articulated locos, draging coal or cruising along with general merchandise.

The Big Boy was built for a job, it did it well. The Allegheny was built to be more versitile (because that is what LIMA was selling with "Super Power"), and its "supposed" mis-use possibly proves how versitile.

But I could be wrong.....

Sheldon 

 

Sheldon,

When you use the term 'engine wheel base' you seem to be referring to the rigid wheelbase of the each coupled driver set.  And while there is no disputing that a 6-coupled engine like the Allegheny or the class A has a shorter rigid wheelbase on each of the articulated engines than an 8-coupled engine like a Big Boy or Yellowstone, I don't know that such a difference has a meaningful effect on the locomotive's ability to maintain speeds or tractive effort on Eastern U.S. mountain railroad mainlines.  There are certainly examples of 8-coupled non-articulated locomotives that were successfully operated on mountainous mainlines in the Eastern U.S.  For example, the N&W J, the C&O Greenbriar, and the AMC 2-8-4 Berkshires all have rigid wheelbases roughly equal to the UP Big Boy, and none of them were considered poor performers in the mountains.  The B&O EM-1 was as close to a UP Big Boy as there was in the East, and they were very successful in all service assignments, including their initial work on the demanding Cumberland division hauling coal and fast freights. 

So I don't quite understand how a UP Big Boy would have been unable to put its low speed advantages to work on the C&O mainline, and outperform the Allegheny hauling coal its own rails.  I also don't see how the Allegheny could do a Big Boy's job on the Wahsatch, or Sherman Hill, since it lacked the starting TE to handle the Big Boy's tonnage ratings.  That is not my definition of being more versatile.

To my mind, the Allegheny was over-boilered for all but the heaviest fast freights, and its design was not suited for C&O's needs, which were hauling heavy coal trains over the Alleghany summit.  This should surprise no one, because the Allegheny wheel arrangement and primary design parameters were selected by the railroad parent company's Advisory Mechanical Committee, with little to no input from the C&O's traffic or mechanical departments.  This is documented in multiple books by Huddleston and Withuhn.  

Scott

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Posted by Overmod on Thursday, December 15, 2022 8:15 AM

Gradual and proportional lateral compliance, particularly on the lead driver pair of a given engine on an articulated, is an essential component of high-speed stability (this is a fact, but I'm not going to substantiate it with citations).  This is different in effect from lateral-motion devices strictly intended to relieve flange forces or permit tighter curve negotiation (also factual, but I'll spare the railfans the MEGO detail)

One specific issue (which I do not know) is whether C&O ran its coal trains at high speed on downgrades or flatter sections, perhaps approximating how D&H post-'38 moved to be more of a one-speed railroad at a higher 'one-speed'.  If that in fact were a consideration, it is comparable to the way the Union Pacific used the Big Boys as pneudyne has laid out, and the use of a higher-speed-capable design might be more justifiable.

On the other hand, by 1941 (and definitively by 1948) chassis and balancing sophistication had reached the point that eight-coupled engines with comparatively small drivers and better steam distribution could perform at high speed.  There was nothing 'special' about the balancing technique on the British Rail 9F 2-10-0s that could not be easily adapted to American practice -- and those locomotives were reputedly capable of 97mph road speed on what I recall to be 56" wheels.  We have been treated to a number of articles in Trains and Classic Trains, and discussion in patent literature, about how lower drivers could be used with correct dynamic balancing, better weight distribution in cast driver centers, the use of Withuhn conjugated duplexing, etc., and of course there is all the discussion about how fast N&W could get Y-class compounds to run.

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Posted by ATLANTIC CENTRAL on Wednesday, December 14, 2022 6:07 PM

Backshop

How many of us operate our cars for the majority of the time in stop-and-go traffic in the city and only occasionally use it at its most efficient speed on the highway?  

 

Very true, however my 7600 lb FORD F250 sees no measureable change in fuel economy from stop and go traffic to highway use at 80 mph on I95.

It's fuel consumption also does not seem to be effected by the work it is doing, that is loaded with construction tools and materials, or pulling my 1600 lb dual wheel trailer with my 1600 lb GRAVELY garden tractor on board, or running light with just me.

The activity of the onboard fuel economy metering suggests it is always getting about 12 mpg.

Suggesting that the available torque and hp from the 6.2 liter gasoline V8 with 385 hp/405 lb-ft torque @ 4500 rpm, is more power than I have yet been able to find a way to use in a way that would fall below its simple hourly fuel consumption rate.

So maybe, an Allegheny was bound to use a similar amount of coal and water slugging a coal train up a hill, or flying down the tracks with a hot shot freight?

But again, I could be wrong,

Sheldon

    

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Posted by Pneudyne on Wednesday, December 14, 2022 5:36 PM
Given that comparison has been made with the Big Boy, it may be noted that the its original mission can be viewed as having had two facets.  Firstly, it was required to take 3600 tons up the 1.14% Wasatch grade, and then run through to Green River, over mostly moderately graded track.  At Green River, the trains were to be handed over to Challengers for movement eastwards.  Evidently UP thought that the Ogden to Green River run would provide for better locomotive utilization than the Wasatch grade alone.  The inclusion of the Wasatch to Green River part of the route effectively meant that the Big Boy would need to have similar speed capability to the Challenger type, hence the 68 inch drivers.  One may speculate that for the Wasatch alone, a 63 inch 2-8-8-4, such as the DM&IR design (albeit with slightly lower axle loading and improved suspension) would have been a reasonable match.
 
Clearly UP was concerned about vertical railhead stresses, hence its fairly tight axle loading limit despite using 131 lb/yard rail.  One may deduce that it was also equally concerned about lateral railhead forces.  The Big Boy was equipped with the full Alco/Blunt “Lever System” of graduated lateral controls, with in particular six of its driving axles having lateral cushioning devices.  UP had first deployed the Alco/Blunt system of the FEF2 4-8-4, which had a somewhat longer wheelbase than was typical for 80 inch 4-8-4s.  It could have been that the Big Boy did not give away much in nimbleness as compared with x-6-6-s articulateds.
 
On excess power/excess haulage capacity, sometimes its provision was seen as contributing to economy, rather than being a diseconomy.  At least, that is the impression may gain from the writings of P.W. Kiefer of the NYC, in respect of the Niagara 4-8-4, about which he said:
 
A basic principle in this development was the incorporation of capacity in excess of that required for current work to be performed, in order to obtain the greatest possible continuity of operation, reduced time and expense for maintenance, and possible shortening of schedules.  That this principle was correct has already been demonstrated by the performance obtained since the engines were placed in regular service beginning in October, 1945.

 

Mileage between tire turnings has averaged about 190,000 with individual engines running as high as 235,000 compared with about 100,000 miles heretofore.  This high mileage is attributed to the high factor of adhesion, together with the design of spring equalization system which uses coil springs at the connection with the frame, the lower initial resistance in trucks and the use of lateral-motion devices on front and intermediate driving axles, all of which increase the flexibility of the driving machinery and permit automatic adjustment against variations due to accumulative wear.

 
The Niagara had not quite the full 'Lever Principle' set of lateral controls.  But it is clear that Kiefer saw graduated lateral controls as a key feature.  The Niagara 4-8-4 was of a size that the Western roads would have deployed on mountain grades, so might have been seen as “overkill” for what was basically a flat route.  But that was not misdesign or misapplication, rather it was Kiefer’s intent, apparently justified by his QED.
 
Steam locomotive power vs. speed curves tend to take the form of an inverted and somewhat skewed approximation to a parabola, sometimes with the initial downslope above the peak being shallower than the corresponding upslope before the peak.  For a given basic design, improvements made in the air-gas-steam cycle to obtain more power and/or greater efficiency not only cause the power peak to move upwards, but also higher in the speed range.  There is usually a lesser corresponding change in the upslope, particularly in its lower reaches.  The upward and outward movement of the power peak might be an objective in itself, or it might be more a byproduct of making general improvements, in which case specific utilization of the new peak might not be a priority objective.
 
 
Cheers,
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Posted by Backshop on Wednesday, December 14, 2022 5:05 PM

How many of us operate our cars for the majority of the time in stop-and-go traffic in the city and only occasionally use it at its most efficient speed on the highway?  

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Posted by timz on Wednesday, December 14, 2022 4:42 PM

Overmod
As a 'fact', I have on my desk a copy of [the drawbar-pull-vs-speed graph for the 2-6+6-6]...

Which shows X pounds at one speed and Y pounds at another -- it's about the same graph as we've seen elsewhere?

So say it shows 97000 lb at 20 mph and 70000 lb at 35 mph. What does that tell us about the cost to operate the engine?

Overmod
the actual cost of fuel and water to operate the locomotive is at a minimum at the peak of the effective horsepower curve

Guess you're saying the fuel/water cost per ton-mile is minimum at 35-45 mph. Need facts to support that. You recall that on test the 2-6+6-6 had about 5.9% drawbar thermal efficiency on a full tonnage train Hinton to Alleghany?

Overmod
...a comparable locomotive design optimized ...

A 16-driver engine, you mean? Preferably compound? Which C&O unaccountably didn't want. Too bad you weren't there to tell them about the optimum design.

Only way you're going to get a horsepower peak at 15-25 mph is to have 16 drivers, or more. You know that, and C&O knew that. So when are we going to hear a fact that you know and they didn't?

Overmod
The [PRR] Q2, a rigid-frame design with one fewer driver pair, develops higher drawbar TE than the Allegheny at any speed

That's test-plant "drawbar pull", isn't it? Where "drawbar" means the rear of a stationary locomotive, ahead of the tender?

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Posted by ATLANTIC CENTRAL on Wednesday, December 14, 2022 3:37 PM

sgriggs

 

 
ATLANTIC CENTRAL

 

 
kgbw49

In an alternate universe it would have been interesting to see how an Allegheny would have fared over Sherman Hill and the Wasatch Range.

I know, I know, different fuel, different builder allegiance, 110,000 lbs tractive effort instead of the Big Boy's 135,000 lbs tractive effort, 12 drivers instead of 16 drivers.

But 13% more tractive effort than a Challenger.

I am just saying it would have been interesting to see an Allegheny give Sherman Hill and the Wasatch Range a go where there was more fast freight opportuniity and a rugged test.

In an alternate universe.

 

 

 

I think an Allegheny could have replaced a Big Boy or Challenger out west with acceptable results.

But neither a Big Boy or an ALCO Challenger could have replaced the Allegheny, or the N&W Class A, in the east.

The Big Boy is not "nimble" enough for Appalachia, and as you point out, the Challenger lacks the power.

I think the C&O/LIMA and the N&W understood the "nimble" issue when staying with 12 drivers, and that is born out by the B&O experiances with EM-1's at higher speeds.

Sheldon

 

 

 

 

I don't agree with this at all.  The Alleghenies were terribly overweight and wouldn't have even been allowed on UP property with their 86,000lbs axle loadings (UP axle load limits during the late steam era were 68,000lbs).  In spite of their axle loadings, the Alleghenies were much less capable than the UP Big Boys in the service these locomotives were intended for.  On their railroads' respective 1.14% ruling grades, the Alleghenies were only rated for 2950 tons, whereas the Big Boys were initially rated for 3600 tons (later increased to as much as 4450 tons).  People like to focus on the maximum horsepower capabilities, but overlook the important performance differences in the speed range where these locomotives operated more frequently.  The Allegheny had 35,000lbs less weight on drivers, smaller cylinders, and lower boiler pressure, all of which are significant drawbacks for a locomotive intended to haul heavy trains on mountain grades.  As a result, the Big Boys developed more horsepower than the Allegheny up to 25mph, allowing faster acceleration from stops, and offsetting some of the Allegheny's horsepower advantage at higher speeds.

With respect to whether the Big Boy would have been nimble enough to handle mainline coal trains in C&O territory, they could negotiate 20 degree curves and were shorter in overall height than the Allegheny.  The only question would be whether clearances to adjacent tracks on the C&O mainline would permit their operation, however let's not forget that the Allegheny was itself a very large machine.

 

Well, you make a good point about the axle loading, east coast roads in general where built with heavier trackage.

As for the nimble thing, I am aware of the abilities of the BigBoy on curves, but locos with longer engine wheel bases cannot maintain higher speeds around sharper curves, loose TE faster on sharper curves, etc.

An over all examination of eastern power vs western powers shows this difference. 

Western roads had/have great "straight a ways" where their tall drivers locos could stretch their legs. And if they had to slow down for some curves in some mountains that was ok.

But in the east straight a ways are rare, every line, level or in the mountains, is one curve after another winding thru the soft hills of the piedmont or around other pre-existing or natural obstacles (Bays, rivers, existing cities, not to mention our smaller, but in some ways more challenging mountains).

So smaller drivers and shorter rigid wheel bases allow moderate speeds on more milage.

The B&O learned this lesson with their 2-10-2's. After dumping one over on the old mainline, they stayed on the straighter Pittsburgh route. The old mainline required the articulated locos, draging coal or cruising along with general merchandise.

The Big Boy was built for a job, it did it well. The Allegheny was built to be more versitile (because that is what LIMA was selling with "Super Power"), and its "supposed" mis-use possibly proves how versitile.

But I could be wrong.....

Sheldon 

    

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Posted by sgriggs on Wednesday, December 14, 2022 3:03 PM

ATLANTIC CENTRAL

 

 
kgbw49

In an alternate universe it would have been interesting to see how an Allegheny would have fared over Sherman Hill and the Wasatch Range.

I know, I know, different fuel, different builder allegiance, 110,000 lbs tractive effort instead of the Big Boy's 135,000 lbs tractive effort, 12 drivers instead of 16 drivers.

But 13% more tractive effort than a Challenger.

I am just saying it would have been interesting to see an Allegheny give Sherman Hill and the Wasatch Range a go where there was more fast freight opportuniity and a rugged test.

In an alternate universe.

 

 

 

I think an Allegheny could have replaced a Big Boy or Challenger out west with acceptable results.

But neither a Big Boy or an ALCO Challenger could have replaced the Allegheny, or the N&W Class A, in the east.

The Big Boy is not "nimble" enough for Appalachia, and as you point out, the Challenger lacks the power.

I think the C&O/LIMA and the N&W understood the "nimble" issue when staying with 12 drivers, and that is born out by the B&O experiances with EM-1's at higher speeds.

Sheldon

 

 

I don't agree with this at all.  The Alleghenies were terribly overweight and wouldn't have even been allowed on UP property with their 86,000lbs axle loadings (UP axle load limits during the late steam era were 68,000lbs).  In spite of their axle loadings, the Alleghenies were much less capable than the UP Big Boys in the service these locomotives were intended for.  On their railroads' respective 1.14% ruling grades, the Alleghenies were only rated for 2950 tons, whereas the Big Boys were initially rated for 3600 tons (later increased to as much as 4450 tons).  People like to focus on the maximum horsepower capabilities, but overlook the important performance differences in the speed range where these locomotives operated more frequently.  The Allegheny had 35,000lbs less weight on drivers, smaller cylinders, and lower boiler pressure, all of which are significant drawbacks for a locomotive intended to haul heavy trains on mountain grades.  As a result, the Big Boys developed more horsepower than the Allegheny up to 25mph, allowing faster acceleration from stops, and offsetting some of the Allegheny's horsepower advantage at higher speeds.

With respect to whether the Big Boy would have been nimble enough to handle mainline coal trains in C&O territory, they could negotiate 20 degree curves and were shorter in overall height than the Allegheny.  The only question would be whether clearances to adjacent tracks on the C&O mainline would permit their operation, however let's not forget that the Allegheny was itself a very large machine.

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Posted by Overmod on Wednesday, December 14, 2022 2:58 PM

As a 'fact', I have on my desk a copy of the PRR 'Dept. of Mech. Eng." starting tractive effort based on MEP graph that was prepared as part of the V1 development.  (In the original this was splendidly prepared, with different colored lines for the different locomotives.) 

The axes for this are 'Drawbar pull - (in) 10,000 Pounds' on the Y axis, and "Speed - Miles Per Hour' on the X axis.

Prominent on this is the trace for the "C&O 2-6-6-6', which perhaps we can factually agree the PRR motive-power department understood at least as well as its counterpart on C&O, although I'm sure there are people who would like to differ.

The interesting thing that immediately emerges from examination of this is that the drawbar pull of the Allegheny at 20mph is close to 100,000lb, which is the practical metric for overcoming train resistance.  By the time you get to the 'horsepower peak' (which is the point of inflection in the trace as drawn)  which is a bit difficult to determine as the curve is relatively flat over a considerable range, the observed drawbar pull at that speed is down to somewhere in the 70,000lb range.

By that measure, there is clearly more train-hauling 'advantage' for C&O to run the engines precisely as they did: the drawbar pull as read directly off the graph translates immediately to the train resistance the locomotive output will 'balance'.

On the other hand, the actual cost of fuel and water to operate the locomotive is at a minimum at the peak of the effective horsepower curve (which can be derived from this graph mathematically with no additional observation).  That is at a higher road speed (and corresponds roughly to the inflection point where the falling curve of tractive effort reverses).  So in essence the C&O is spending more to run the locomotive on the heavier train than it would if it ran where Lima designed the locomotive to go (I assume that Eric Hirsimaki is not talking out of his hat when he discusses this; I certainly see no technical reason to dispute the idea).

Obviously we know how C&O considered the tradeoff.  Mr. Zukas may have the specific information about C&O crew costs or union agreements that would justify the lower unit cost of crew operation represented by the heavier tonnage vs. the longer time required for the train to operate a given distance, which is likely a large part of the reason C&O operated the locomotives as they did.

But this in no way establishes that a comparable locomotive design optimized to actually make peak power from the same steam-generation capacity with peak horsepower at the effective speed range wouldn't have had exactly the same operating manpower cost, with an even higher effective drawbar TE at comparable speed, which is what I was arguing and what Mr. Zukas seems to be doing his obstinate best to misundestand and cavil over at the same time.

I've posted the B&W scan of the graph several times over the years, so it should be at least possible to find somewhere, probably in one of the steam-technology threads from about a decade ago.  I don't have the immediate equipment to scan it for posting again, but I can certainly do so if anyone who wants facts about steam design wants to see it.

As a couple of interesting asides: the Allegheny trace was only recorded up to 60mph, which is about 4mph higher than the point where the 6-8-6 S2 turbine starts producing more TE at speed.  The Q2, a rigid-frame design with one fewer driver pair, develops higher drawbar TE than the Allegheny at any speed, but there is something of a 'ringer' in this because PRR is quietly including the high-speed booster as part of the trace, and they cut this out at suspiciously high speed (about 37mph) which probably not coincidentally is precisely where the falling trace due to steam consumption from the booster just approaches the Allegheny's.

The V1, which at the time of the graph was still the mechanical double turbine, is interesting.  Its starting TE, despite it having many of the same ghastly low-speed steam consumption characteristics as the S2, is 5000lb or more over the Allegheny's starting DBTE, but it falls below at about 12mph and then rises above again right around 20mph, after which is sharply diverges; by 55mph it had prospectively had over a 15,000lb advantage, and produced the same DBTE that the Allegheny shows at 60mph at over 75mph.  (Not that that would have mattered much after PRR went back to 50mph freight, but it would have been significant in 1944).

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Posted by timz on Tuesday, December 13, 2022 7:08 PM

daveklepper
Is the horsepower vs. speed analysis fact or opinion?

Depends what you mean by "analysis". Everyone agrees the dbhp-vs-speed graphs for the Allegheny and the N&W 2-6+6-4 slope upward from 0 to 40-45 mph. That's a fact, close enough. Some fans like to think that means the Allegheny and A were "misapplied" on upgrade coal trains. No facts are involved in that conclusion -- the necessary facts are unknown.

Whatever facts do exist were known by C&O and N&W better than today's fans know them, of course. We'll never know how today's fans can imagine they know better than C&O and N&W motive-power people did in the 1940s. (Good a guess as any: the fans don't know what "fact" means.)

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Posted by daveklepper on Tuesday, December 13, 2022 5:42 PM

Hmmmm!   You've raised a question.  Is the horsepower vs. speed analysis fact or opinion?   Grades. loads. tractive-effort and possible speeds?

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Posted by timz on Tuesday, December 13, 2022 10:33 AM

Overmod
I have factually pointed out, over and over and over ....

Overmod
By objective and easy-to-substantiate technical reasons....

Maybe we've found the root of the problem -- what does "fact" mean?

"C&O 1600 left Lima's plant on (date)."

Once we fill in the date, that's an example of a fact. Everyone agrees on it.

"Earth is round."

That's pretty much a fact, tho some people like to disagree with it.

So now it's up to the readers, again: can anyone find a fact anywhere in the same county as the quotes above?

BigJim mentioned the grade at a spot on the Virginian -- I assume it's a fact that that's what the NS track chart shows. Aside from that, can anyone find a fact anywhere in this thread, written by any of us? Lots of opinions, lots of surmises, but roughly zero facts. Nothing wrong with that -- just don't imagine you're reading facts.

 

Overmod
(Perhaps that will be simple enough for you to grasp.)
Fraid not. 

Overmod
N&W routinely used 70"-drivered As on coal trains limited by Y-class compound road speeds.... it was not an efficient use of that type of locomotive.

This is news -- not just C&O, but N&W too, would've done better with a railfan on the payroll. No doubt the same was true of dozens of US railroads? Not to mention the rest of the world.

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Posted by Overmod on Monday, December 12, 2022 6:07 PM

In general, it would make great sense to standardize on the minimum number of large steam designs; we might compare the "lower" nominal power output of the Allegheny design at low speed with the 'competing' horsepower of alternative designs on C&O or elsewhere, and find it perfectly acceptable... as long as we didn't make up coal trains expecting that the Allegheny would be making its vaunted 7000+hp on them. 

There was a funny thing going on with C&O in the late '40s: they had two flavors of very heavy Hudson, one very interesting set of radical rebuilds of F-19 Pacifics into a completely different type of Hudson, the series of Greenbrier 4-8-4s, and the M-1 turbines, all predominantly passenger engines -- but there appeared to be no attempt to adapt the Allegheny type to perform the job of the failed M-1s on modern streamliners west of Charlottesville, as I think N&W was planning to do as its 'competition' to Cincinnati (using the last As with lightweight rods) if that traffic had in fact competitively developed rather than cumulatively failed everyone.  That would have given a '4-8-4-and-a-half' with its desired speed range right smack near the peak of the horsepower curve -- admittedly this is sort of overkill for contemporary C&O traffic, but not the proposed Chessie, or other Robert R. Young trains prospectively full of special cars and amenities and axle-driven power requirements...

The thihg that I think bothers me is that the same period marks the practical mainstream application of better balancing on heavy power, which for example together with modulated IP injection could have made relatively high-speed engines out of N&W compound 2-8-8-2s, making the engines actually match the legend N&W seemed to be fabricating for them in the early-to-middle '50s.  A 2-8-8-6 with many common components shared with the Alleghenies (including most of the steam-distribution parts) might easily have had all the necessary merchandise speed at tolerable augment and yaw, but be wholly suited to coal trains right down to adhesion limit.  That shouldn't have taken Lima and the AMC much time to develop, and kept many components common between the two engine classes.  But that is merely speculation.

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Posted by Leo_Ames on Monday, December 12, 2022 3:19 PM

While I'm in agreement with your main points, I think it's worth again to state that the C&O went back three years after the conclusion of WWII and bought 15 additional copies of this design.

So I'm not convinced that they exactly felt that they were stuck at the end of WWII with 45 expensive locomotives without a clear fit in the postwar C&O to take advantage of that large investment (And if so, that feeling couldn't of lasted for long when they soon expanded the fleet to 60 examples).

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Posted by Overmod on Monday, December 12, 2022 1:58 PM

timz
Overmod
I am not saying C&O was 'stupid'

That's simply your -- frankly pathetic, but that's not important right now -- presumption.  I have factually pointed out, over and over and over by this point, that the Alleghenies would make nowhere near their intended economy, would suffer far more wear, and would have significantly lower effective drawbar pull at speed, at the speed range C&O typically ran them in mineral service, than they would have if C&O had run them as Lima/AMC designed them.  You have nothing to contribute to that but clumsy ad hominem attempts at insult, based on the logical fallacy both of appeal to authority and that people in control of a BIG RAILROAD might have made expedient rather than efficient use of a particular design of modern power... and, implicitly and essentially, that the BIG RAILROAD knew more about motive power than a BIG LOCOMOTIVE COMPANY.  (Perhaps that will be simple enough for you to grasp.)
One of these years you might actually learn enough steam technology to understand what I am saying I know, and what it is they might have chosen to accept.  But I doubt you'll ever try; it's so much easier to be a... what was the expression you used?... stuffed shirt about it.
Overmod
My opinion is that C&O bought the engines first for capability at merchandiser speed, and second as wartime engines.  At the end of the war they had a stock of very expensive locomotives that C&O had comparatively little distinctive use for ...
Good lord! You think when C&O ordered 45-or-whatever-it-was Alleghenies, they didn't plan to haul coal to Alleghany with them?
I have no idea what their intentions might have been, only that the motive power as designed was far, far from being optimized for that particular service.  By objective and easy-to-substantiate technical reasons.
 
Were there other railroads that chose to use higher-speed power the same way?  Clearly the N&W routinely used 70"-drivered As on coal trains limited by Y-class compound road speeds.  You'll notice I don't accuse them of being 'stupid', either -- but I will say it was not an efficient use of that type of locomotive.
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Posted by timz on Monday, December 12, 2022 10:34 AM

Overmod
I am not saying C&O was 'stupid'

True -- you're just saying they weren't as smart as you. One of these years you ought to try to tell us what you know that they didn't.
Overmod
My opinion is that C&O bought the engines first for capability at merchandiser speed, and second as wartime engines.  At the end of the war they had a stock of very expensive locomotives that C&O had comparatively little distinctive use for ...
Good lord! You think when C&O ordered 45-or-whatever-it-was Alleghenies, they didn't plan to haul coal to Alleghany with them?

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Posted by BaltACD on Monday, December 12, 2022 10:28 AM

Backshop
Using Trains Guide to North American Steam Locomotives, I count the SP as having 266 x-8-8-x locomotives. I count N&W as having 231.  What makes this most impressive is that the N&W in the steam era was a relatively small railroad.  It didn't get further west/north than Columbus and Cincinnati.  It didn't include what many of us remember from our lifetimes, the VGN, WAB, NKP, WLE, etc.

Videos I have seen - NW needed multiple engines on both ends of the size trains they were operating over the grades of their territory.  SP had much more mileage to cover but had less need to use multiple engines on both ends of their trains.

Never too old to have a happy childhood!

              

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Posted by Backshop on Monday, December 12, 2022 9:46 AM

Using Trains Guide to North American Steam Locomotives, I count the SP as having 266 x-8-8-x locomotives. I count N&W as having 231.  What makes this most impressive is that the N&W in the steam era was a relatively small railroad.  It didn't get further west/north than Columbus and Cincinnati.  It didn't include what many of us remember from our lifetimes, the VGN, WAB, NKP, WLE, etc.

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Posted by kgbw49 on Monday, December 12, 2022 7:08 AM

That is a great question!

SP had 195 of the AC-4 through AC-8 and AC-10 through AC-12 4-8-8-2 classes.

SP had 12 of the AC-9 2-8-8-4 class.

SP also had quite a number of the 2-8-8-2 configuration.

Hmmm.

Perhaps Norfolk & Western with their various Y 2-8-8-2 classes gives SP a run?

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Posted by Erik_Mag on Monday, December 12, 2022 12:39 AM

Which brings up a question. The SP had a lot of cab forwards, did any railroad have more 16 driver locomotives than the SP?

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Posted by ATLANTIC CENTRAL on Sunday, December 11, 2022 10:24 PM

kgbw49

 

 
BaltACD

In 1947 the B&O had a mail train being hauled by an EM-1 #7625 that derailed near Oakland, MD at 40 MPH with a cause listed as "Irregularities in alinement, surface and gage of track combined with slack closure".  Subsequently the B&O rarely if ever used EM-1's on passenger schedules.

https://planeandtrainwrecks.com/Document?db=DOT-RAILROAD&query=(select+130+(byhits+(field+RAILROAD+(anyof+BALTIMORE))))

 

 

 

Ironically Southern Pacific with their reversal of their articulated 2-8-8-4 locomotives for safer-for-crew operations in tunnels resulted in a four-wheel lead truck and satisfactory performance on passenger, mail and fast freight.

https://www.railpictures.net/photo/819346/

 

The cab forward also had the advantage of the pivoting engine following, which also added to its high speed stability.

Sheldon

    

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Posted by kgbw49 on Sunday, December 11, 2022 10:03 PM

BaltACD

In 1947 the B&O had a mail train being hauled by an EM-1 #7625 that derailed near Oakland, MD at 40 MPH with a cause listed as "Irregularities in alinement, surface and gage of track combined with slack closure".  Subsequently the B&O rarely if ever used EM-1's on passenger schedules.

https://planeandtrainwrecks.com/Document?db=DOT-RAILROAD&query=(select+130+(byhits+(field+RAILROAD+(anyof+BALTIMORE))))

 

Ironically Southern Pacific with their reversal of their articulated 2-8-8-4 locomotives for safer-for-crew operations in tunnels resulted in a four-wheel lead truck and satisfactory performance on passenger, mail and fast freight.

https://www.railpictures.net/photo/819346/

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Posted by Overmod on Sunday, December 11, 2022 4:19 PM

timz
If anyone is interested in this discussion, you ought to take a look at the January 1931 Railway Age article on C&O's first replacement of 16-driver engines.

Look back earlier.  C&O was among the first, if not the first, to build 16-driver articulated engines with simple expansion, and only slightly later to substitute very large 2-10-4s for those engines.  Neither of those qualifies as 'stupidity'.  

To make my opinion perfectly clear, I am not saying C&O was 'stupid' for abusing the Allegheny locomotives in coal service.  The Allegheny represents the flower of both Lima engineering and the AMC.  Lima and Woodard made their share of weird experiments and proposals that we've come to recognize as zany or worse... but there was no stupidity or ignorance involved in those.

It is somewhat possible that Lima sold C&O a line about the suitability of the design for heavy service -- C&O had what was probably the highest permissible weight on drivers of any road, Eastern or otherwise, and the early Allegheny examples certainly flirted with it.  This is (in my opinion at least) not as egregious as Baldwin telling N&W that the TE-1 would be capable of 65mph because the traction motors were nominally geared for that speed; apparently N&W did not figure out what a whopper this was until the locomotive was over its early teething troubles and the time came to try running at that advertised speed.

My opinion is that C&O bought the engines first for capability at merchandiser speed, and second as wartime engines.  At the end of the war they had a stock of very expensive locomotives that C&O had comparatively little distinctive use for, so it's not surprising they worked them in the services they could, a bit like farmers in the Depression who found that cutting the bodies off big Packards and the like could enable their effective use as flatbed or stakebody trucks.  This is not 'economical' in the same sense as Tuplin's report of the Niagara, but it is practical use of an asset to produce at least some ton-miles, even if well short of the potential economy of running them closer to the horsepower peak.

There is a very old tendency, mocked effectively by Sinclair's Gilderfluke Patent Locomotive, to weigh steam-locomotive designs primarily in terms of thermodynamics, including the various methods of Rankine heat recovery.  However, railroads could much more properly choose to operate locomotives as commodity generators of ton-miles -- as productive assets rather than economizers.  A pointed example would be the D&H high-pressure engines, which were delightful on 5mph drags, but incapable of showing the practical economies of the Challengers... but this required changing the railroad operations to permit high-speed freight working.  Had D&H bought Challengers and then relegated them day-in day-out to slow coal drags... it would have been a waste comparable to C&O's operations, and it is that waste, not overall financial asset utilization, that is the subject of the Allegheny technical discussion.

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Posted by timz on Sunday, December 11, 2022 11:21 AM

If anyone is interested in this discussion, you ought to take a look at the January 1931 Railway Age article on C&O's first replacement of 16-driver engines. The writer doesn't comment on C&O's stupidity -- maybe he figured no need to mention it, since it was so obvious.

(Too bad -- that volume of Rwy Age isn't on Hathitrust.org. Anyone find it anywhere else?)

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Posted by ATLANTIC CENTRAL on Sunday, December 11, 2022 9:10 AM

daveklepper

If the C&O had the opportunities to run fast?   The Virginian?

Where on the Virginian?   And were the Alleghenies actually used where they could run fast?   Or where the Greenriars (4-8-4s) thr premium power there?

Perhaps the C&O was hoping for an expansion of the high-tarrif merchandise business that would really use the speed characteristcs. 

 

 

 

I'm not an expert who has the whole history of the C&O, or any railroad, committed to memory.

But from what I have read, and been told by those who have done more research than me, the C&O was very progressive and optimistic in the post war era, even if that optimism was unrealistic.

I think everyone in this discussion who has not read "LIMA - super power steam locomotives" by Dixon and Kohles needs to.

The developement of the the super power concept gave steam locomotives a multi purpose ability they had never had before. 

Enough steam, the perfect balance of driver size, piston size and stroke, roller bearings, better balancing, and moderm boiler efficiency gave these locomotives a dramaticly wider range of capabilities than previous designs.

The early 4-8-2's were the first "hint" that a steam locomotive could excel at both speed and power. Look at the list roads who used that wheel arrangement and how they used them - lots of passenger and freight, by a group of locos with similar specs.

LIMA rasied this to an art form, while the other builders played catch up in this area.

The Allegheny was the ulimate test of how big and powerful such a locomotive could be. It worked. 

Even if only half of its potential was used on a regular basis.

And the N&W did the same thing on their own, in their own shops.

People get all excited about the BigBoy, and it is impressive, but the fact that an Allegheny is what it is, on 12 drivers rather than 16, is way more impressive in my mind.

Long wheel base locos beat up track, this is no secret. There as been enough written about the C&O T-1 in this regard. I believe that was another reason for the Allegheny. The T-1's needed to stay in the flater, straighter parts of the line..... Something more nimble, yet powerful, was needed.

But I'm by no means the expert, just a modeler and casual railfan.

Sheldon

 

    

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Posted by daveklepper on Sunday, December 11, 2022 5:35 AM

If the C&O had the opportunities to run fast?   The Virginian?

Where on the Virginian?   And were the Alleghenies actually used where they could run fast?   Or where the Greenriars (4-8-4s) thr premium power there?

Perhaps the C&O was hoping for an expansion of the high-tarrif merchandise business that would really use the speed characteristcs. 

 

 

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Posted by ATLANTIC CENTRAL on Saturday, December 10, 2022 1:43 PM

CSSHEGEWISCH

Of course, neither the UP Challenger nor the Big Boy were designed for drag freight service.

 

And there you have it, the design of both the Class A and the Allegheny made them more versatile, able to run fast, or slug it out with a heavy load. And plenty nimble enough to maintain moderate speeds in the winding turns of Appalachia.

Could it be that the designers knew exactly what they were building?

Sheldon

    

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