Modern Steam in North America (An Informal Poll)

[MopacBarrettTunnel]

Wake Up and smell the smoke.

My vote is for the Biggest, Strongest and Sharpest American Built Steam Engine.

U.P.'s 4-8-8-4 Big Boy.

Stand track side and Feel the Power

While not trying to upset anybody...

The Pennsylvania S-1 6-4-4-6 was BIGGER than the UP 4000 class (ie just as wide but LONGER!)

The C&O Allegheny 2-6-6-6 was HEAVIER than the UP 4000 class and some people suggest that it was more powerful.

So what was it that made the UP 4000 so good, and if so, why was it kept in one location for its operating life?

M636C 

 

 

The right tool for a very specific job? 

How long did any of the other engines you mentioned last on their respective assignments?  Were they as spectacularly successful as UP's #4000's?  "Bigger" might be of importance to some, but the bottom line was and remains PERFORMANCE - and in this regard, the big Boy has no competition, save perhaps N&W's Y-4/5/6 classes of Mallets, and even they don't really count as a "modern" design.  Sure, others might have weighed more or could develop more gross horsepower - but could they have utilized those traits as productively as UP's 4000's did on a daily basis from 1941 until 1959?  If so - did they?

Big Boy has NO comparison - it's that simple.  Certain "bragging rights" might not be his, but his performance as a specific tool for a specific job leaves nothing to apologize for, and the UP itself knew this, when it came time to ursurp steam for good - which is why the turbines came of age {after a fashion}, as the diesels of the day didn't have enough horses from a SINGLE unit, much less two.

You raise a good point about the Big Boy and the fact that it was well utilized while in service--basically moving fast freight over a sawtooth profile, which it was very good at doing. 

However...I find the C&O Allegheny to be the better design, that, unfortunately, was not utilized properly most of the time.  Compared to the Big Boy, the Allegheny developed higher horsepower at speed, had a larger boiler and greater steaming capacity, and had a much higher factor of adhesion (4.61 as opposed to Big Boy's 3.99).  That latter figure more than makes up for the Allegheny's lesser tractive effort, which becomes something of a meaningless figure, no matter how great it may be, on a locomotive with a low factor of adhesion.

Having said that, the Allegheny performed quite well moving fast freight over the Allegheny and Northern Subdivisions, as it should have--it was the ultimate locomotive built according the Super Power principles.  Notice the Allegheny's firebox is supported only by the six wheel trailing truck--Big Boy and all of the Yellowstones had fireboxes extending over the last two sets of drivers.  Doesn't make them any less modern, it just means they weren't an outgrowth of Woodard's Super Power steam design.

The biggest problem with the Allegheny was that it wasn't utilized properly often enough, but instead was used primarily in push/pull coal drag service over the Allegheny Subdivision.  No other articulated could have done a better job here, but with 67" drivers these engines weren't meant for such slow-speed tasks where their high horsepower couldn't be truly utilized.  On the Northern Subdivision they fared a little better, and were able to move 160 car 13,500 ton coal trains at decent speeds, and were able to bypass pusher service at Limeville Bridge, something the C&O's T-1 2-10-4's could not do.

So in the end, performance wise, Big Boy could be rivaled, and perhaps surpassed.  I imagine an Allegheny would have done an equal job if sent to the UP.    

<> Many valid points, my Friend!!  While I'm an unabashed Big Boy partisan, I'm also quite aware and respectful of his counterpart's abilities and virtues.  While the Allegheny was a damn fine design, it wasn't really exploited to its' full potential.  Neither was Big Boy, for that matter although he came closer than most.  The Allegheny's 4+ factor of adhesion clearly gives it the "win" in the gross weight category, and is certainly more impressive than Big Boy's 3.9 - until you realize that even the earliest successful road diesels operated comfortably in the 10-20% range of adhesion!! 

<>That being said, what we're really doing with this debate is discussing semantics.  Truth be told, the 2-6-6-6 quite possibly have been Big Boy's equal or superior, had Uncle Pete been looking away from Alco-design help.  Clearances wouldn't have been as big an issue with the Allegheny, to cite an instance.  Big Boy's drivers were only an inch larger {I think - I'm too lazy now to look it up}, so speed wouldn't have suffered too much.  After that, it's down to the details; servicing / turnaround times; thermal / combustion / fuel and water efficiency, ease of repair and wear-and-tear on the infrastructure, etc.  A totally subjective discourse, in other words.

<>All in all, it still makes for good discussion fodder, no?<>

<>

[Lost World]

Nothing I would rather discuss...