Start Foaming..Lets See the STEAM!!!

[chicken45]

Hey John,
That reminds me why didn't you want me to mention all of those UP casting you ordered???


Bahahaha

Ooooh buuuuurn!

[superturbine]

Hope you guys don't mind me posting the 4-12-2 pic here also.

[robert3985]

Man. Almost makes me want to model UP.
Almost. Why did they have such HUGE locos? Was it for more power and less curves out west?

Josh, The reason UP had so many HUGE locos (2-10-2's, 4-12-2's, 2-8-8-0's, 4-6-6-4's and 4-8-8-4's) during the steam era, and HUGE diesel-electric and turbine-electric engines simultaneously with big steam during the 1950's, was because of the 65 mile stretch of 1.14% grade between Ogden and Wahsatch Utah.

The "magic" train weight was 3,000 tons and both the three cylinder 4-12-2 9000 class engines and the simple-ized 2-8-8-0 "Bullmooses" were rated at 3,000 tons between Ogden and Wahsatch.  After Wahsatch, the grade leveled out and more tonnage could be pulled, so often, trains up to 4,000 tons were made up in Ogden/Riverdale and a helper was attached to the rear for the run up the grade to Wahsatch, then cut-off and returned light for the 65 mile downhill drift to Ogden/Riverdale to be turned and put on the rear of another 3,000+ ton train. 

However, the helper situation made for doubling the maintenance, doubling the fuel/water usage, and doubling the engine crews.  It also made for extending the time because both coal fired primary and helper engines had to be refueled at Echo, and engines assigned for this run had tenders which were designed to provide just enough fuel and water to get them to Echo, where they were watered, sanded and coaled up to continue on upgrade to Wahsatch and beyond.  Wahsatch had a water tower and standards for added water if needed, usually for the helpers.

So, the engine the UP felt it needed would pull at least 3500 tons from Ogden/Riverdale to Green River, stopping at Echo for water, sand and coal, at an average speed of 18 MPH without a helper.

UP management was extremely pleased with the Challenger 4-6-6-4 engines (especially the "Big" Challengers), but they still needed helpers when tonnage exceeded 3,000 tons, but eliminated running helpers on passenger trains as well as running separate sections, which is why the Challengers worked both freight and passenger trains.

In conjunction with ALCO, Otto Jabelman, head of UP engineering, designed a "stretched" Challenger, and its dimensions were measured in fractions of an inch, and was literally the largest locomotive that could operate on existing trackage, bridges and tunnels in Weber Canyon on the Wahsatch grade.  In the Summer of 1941, nearly every curve between Ogden and Green River was re-aligned to accommodate the huge locomotive, and the walkway design on the engine were narrowed from 24" to 16" for added clearance.  At least one mainline siding was eliminated because of the realignment and three largest-turntables-in-the-world were installed in Ogden, Green River and Laramie to make turning Big Boy possible, and new 131 lb. rail was laid.

In September of 1941, the first Big Boy (4000) made its initial revenue run from Ogden to Green River with 3,500 tons which it made in six hours and fifty minutes.  It was immediately turned and came back with 120 empties.  It was then turned and went back to Green River with 3,870 tons, which later was determined to have been more than 4,000 tons due to a miscalculation in the Riverdale Yard.  3,500 tons to 4,000 tons equals 45 to 55 loads and 10 to 20 empties.

Trains pulled by lesser engines, as well as diesel and turbine lashups still had helpers assigned, and in the 1950's, those engines were usually TTT 2-10-2's, 3700 Class oil-fired Challengers and the occasional 9000 class three-cylinder 4-12-2, all of which cut off at Wahsatch, turned on the wye there, and drifted light back to Ogden/Riverdale.

So, on a typical day in 1953, you could see Big Boys, Challengers, 2-10-2's, and 4-12-2's within a couple of hours of train watching, with a possible 2-8-8-0 Bullmoose thrown in.  Of course that doesn't include the MacArthers (Mikados) pulling two daily locals, and all those FEF-1, 2's, and 3's pulling passenger trains or any of the diesel F-3's, F-7's, GP-7's, E's and the new Baby Turbines (without tenders)!!...with the occasional PA/PB, FA/FB freights and maybe an Erie-Built pulled train...

There were a total of 25 Big Boys and they did their job day after day, year after year, with an exceptionally excellent availability rate, which the FEF's and Challengers shared along with several design elements. 

I love this era and location (I live here too)...Hope this answers your question!

[Lemosteam]

Robert, really nice dissertation.  That short bit answered many of my UP questions regarding thier steam locomotives.  Thanks for that.

[chicken45]

Great story, Bob! Thank you! You tell it so well!

[Ed Kapuscinski]

Robert, really nice dissertation.  That short bit answered many of my UP questions regarding thier steam locomotives.  Thanks for that.

Yes! I had always been curious too, and that was incredibly helpful!!!

Thanks Bob!

[chicken45]

Were the Big Boys the most powerful of those locos?

I heard that the Pennsy Q2 was supposedly more powerful but I can't confirm that.

[Nato]

              I do not know much about the Pennsy Q2 ,but I do know that there has always been a debate wheather or not the DM&IR Yellowstone 2-8-8-4 locomotives or The Big Boy had more horse power. The figures for both were very close. Bob,even being aware of the facts,you presented them in a nice consice way. Nate Goodman (Nato).

[superturbine]

Bob,
Your explanation  gave me a thrill up my leg and a tear in my eye ....... well done Sir!!

[chicken45]

I just did some rudimental Googling and came across the ATSF 3000 class 2-10-10-2 and those triplexes that the Virginian had. 2-8-8-8-2 and 2-8-8-8-4. Can't even imagine seeing those monsters.

[Lemosteam]

http://www.trainorders.com/discussion/read.php?1,776106


Nuff Said. 

[Cajonpassfan]

John, great link!
Because of the variety of engine types and assignmens, there's a lot more to the question than meets the eye...ultimately it was about drawbar horsepower over a specified speed range on a particular stretch of mainline.
Thanks for posting it,
Otto K.

[robert3985]

The question of which steam engine was the "most powerful" is a question that us modelers love to posit.  However, each loco built for/by each road was built for a specific purpose, area and usage.  Some may have been more powerful than the Big Boy, but I doubt that many were more successful, as Big Boy exceeded its design parameters and until the advent of the GTEL Turbines (which ran simultaneously with Big Boy), was the only UP engine capable of pulling up to 4,450 tons up the Wahsatch Grade without a helper.  Big Boy was rated to 75mph and would regularly do that when its run was extended from Ogden to Cheyenne.  Big Boy service life was from 1941 until 1959, and all 25 lasted until July of that year.

Union Pacific got a lot of PR off of the Big Boy, and it was a particularly good looking, well proportioned locomotive, comfortable, reliable and easy to fire, with an 18 year life span.  Whether there were other engines "more powerful", "heavier", or "larger" is really of no consequence as Big Boy was near perfect for its designed task and was a deserving culmination of articulated steam power on the UP, and crews, management and local fans hated to see its fires finally die.

[eric220]

In regard to which loco was the "largest", SteamLocomotive.net had a good writup, but it seems to go to a broken link now. Basically, the conclusion was that from a technical standpoint, the Big Boy was not the largest. There are locomotives that were longer, heavier, more powerful, etc. The Big Boy never "wins" a category, but it is the only locomotive that consistently places in the top 5 or so, no matter what criteria you pick to call the "largest".

Edit: Found it. http://www.steamlocomotive.com/misc/largest.php

[delamaize]

I got the trackwork done on the new-to-me layout, and decided to take the A4 for a spin.
WARNING: Crappy Cell phone video!

It's Nice to see her running in some scenery for one, rather than the plywood central!!