4-8-4 comparisons

Of the existing 4-8-4's that are operable, including the #614 as possibly so, which of them would be able to run a string of 15 heavyweight passenger cars at highest consistent speed? I know that driver diam vs. tractive effort/horsepower will enter the discussion, but for comparison's sake two scenarios...same string of cars behind each loco (1)...dead flat straight track....(2) and up hill on UP, Cheyenne to Dale up Sherman Hill via Borie.

Why stop at just 15 cars?:P

Here is the C&O 614 pulling 22 cars at 79 mph:
http://youtube.com/watch?v=AhGoR1cpdrM&feature=related

Even better, here is the C&O 614 pulling 25 heavyweight cars at 79 mph:
http://youtube.com/watch?v=lAQwPc4JmS4

There is a reason why the 614 is called SuperPower!!

I'll go along with that, but will add virtually every Northern still in operating condition that is alive and well today. # 3751, # 4449 et al are included. And for good measure add # 844.

By the way when they start running consists of over 15 cars, and especially over 20 cars, they usually have about 6000 hp or more of diesels behind the Northern. That is for climbing hills, high speed, and dynamic braking going down hills.

pennsy wrote: By the way when they start running consists of over 15 cars, and especially over 20 cars, they usually have about 6000 hp or more of diesels behind the Northern. That is for climbing hills, high speed, and dynamic braking going down hills.

No Dismal-Electrics needed with the C&O 614

The 614 took the same 25 car train from this video:

http://youtube.com/watch?v=lAQwPc4JmS4

and stormed up and down the infamous B&O 17 Mile Grade (2.7% maximum gradient!) unassisted with no Dismals in sight. Very impressive considering the 614 is designed to run as high as 120 MPH

It did the same thing on the Sand Patch Grade with no Dismals either.

The C&O 614 also operated the Amtrak Cardinal through West Virginia with higher speed and better time, than the normal 3 F40 dismals could manage!

Interesting question! Sounds like some numbers would help the discussion. All stats unless noted are from the San Bernadino Railroad Historical Society & can be found at http://www.sbrhs.org/Pages/484com.html

Engine | Drivers | Engine Wt |Wt w/tender | Tract. Eff. | Cyl. | Blr Pres.

GTW 6325 | 73" | 403,000 lbs | 673,500 lbs | 59,000 lbs | 26x30 | 250 lbs
SSW 819 | 70" | 419,800 lbs | 737,500 lbs | 61,564 lbs | 26x30 | 250 lbs
RDG 2100 | 70" | 447,300 lbs | 844,000 lbs | 68,000 lbs | 27x32 | 240 lbs
MILW 261 | 74" | 460,000 lbs | 824,100 lbs | 62,040 lbs | 26x32 | 250 lbs
SP 4449 | 80" | 475,000 lbs | 865,750 lbs | 64,800 lbs | 25.5x32 | 300 lbs
ATSF 3751 | 80" | 478,100 lbs | 874,346 lbs | 71,719 lbs | 30x30 | 230 lbs
C&O 614 | 72" | 482,200 lbs | 865,530 lbs | 68,300 lbs | 27.5x30 | 255 lbs
SP&S 700 | 77" | 485,500 lbs | 871,550 lbs | 69,500 lbs | 26x31 | 260 lbs
UP 844 | 80" | 486,340 lbs | 907,890 lbs | 63,800 lbs | 25x32 | 300 lbs
N&W 611 | 70" | 494,000 lbs | 873,000 lbs | 80,000 lbs | 27x32 | 300 lbs
ATSF 2926 | 80" | 510,150 lbs | 961,000 lbs | 86,922 lbs | 28x32 | 300 lbs

SSW 819, N&W 611, ATSF 2926 and C&O 614 are not currently operational.

C&O 614 was built with a booster that increased its tractive effort to 80,700 lbs, but it is no longer equipped with it. Anyone know if it had it during the videos that have been posted?

RDG 2100 was built with a booster that increased its tractive effort to 79,100 lbs. Not sure if the booster is still there or if it is functional.

SP 4449 has a seldom-used trailing-truck booster that increases its tractive effort to 77,760 lbs. (Source: http://www.steamlocomotive.com/northern/sp.shtml)

ATSF 3751's tractive effort as built with friction bearings was 66,000 lbs. It is now equipped with roller bearings, which affects TE.

ATSF 2926's tractive effort estimated. See the source page for more info.

My Thoughts: Based on the numbers, even without the booster, 614 would be one of the strongest, and has relatively small drivers, which might give it an edge on hills. Too bad N&W #611 isn't still operational, It would be a leading contender.

614's booster was made inoperable by the ACE tests in 1985... they ran the tests for less then a week before the booster broke down.

If Ross removed the booster from the engine after those tests, its news to me. I was under the impression that they repaired the booster after the ACE tests.

Its not just about tractive effort numbers... cylinder diameter, driver diameter, boiler diameter, boiler pressure, superheat, bearing style all affect pulling ability.

One other number I'd like to know is the factor of adhesion for each unit. While it doesn't directly affect pulling power (since it is a mathmatic number) it would show which engines could stand to have their boiler pressure raised to increase pulling power.

the higher the pressure, the larger the cylinders and the smaller the drivers... those combinations would be most important for the engine on the hill, while higher pressure, larger drivers and larger boiler diameter would be more important on the level. Shorter piston stroke will also help on the level, reducing the occilating forces from the reciprocating masses.

I don't have any firsthand knowledge about 614's booster, but the specs on its official website (http://www.co614.com/614history.htm) also give the tractive effort as 68,300 lbs, which would suggest that the booster is at least not operational. Hopefully someone knows for sure. It would certainly make a difference.

There are some Ross Rowland quotes there too about 614's capabilities:

"the Port Jervis excursions are the only place in the free world where one can ride behind steam (with no diesels anywhere in the consist) at speeds up to 79 M.P.H."

"the 180 mile round trip to Port Jervis...gives the 614 a real challenge in bringing the 24 car long train up the 1%, 13 mile long grade..."

The 24 car train probably included a lot of streamlined cars, but it should be at least equivalent to train of 15 heavyweights, if not more. So, 614 unassisted could get the train to 79 mph (and probably faster) on level track, and could pull it up a long 1% grade at a reasonable speed. Although, I suspect most, if not all, of the 4-8-4s could offer a similar performance.

The numbers don't give a clear "winner," but they do offer a basis for comparison, which is why I posted them. And it is certainly possible that some engines might do best on the flat run, while others might do best on the grade, so there wouldn't be a single "winner."

Boosters ??? Well now, does everyone know that 4449 has a tender booster ? Rarely used.

Does everyone also know that Union Pacific didn't believe in boosters and never had them. They felt that given sufficient steam pressure, large enough cylinders etc. and large enough driver diameter, boosters were not needed.

Pennsy, thanks for the reminder about 4449's seldom used booster. Its actually a trailing truck booster, and was recently converted to roller bearings. Pictures of the conversion are at http://www.sp4449.com/03photos/menatwor ... index.html

4449's website doesn't have specs, but according to http://www.steamlocomotive.com/northern/sp.shtml the booster increased a GS4's tractive effort to 77,760 lbs. I added a note to my previous post.

Thanks for the correction. I checked my Bachmann HO model of 4449 and the brochures that came with it to make sure. Not that common to have a trailing axles booster. Usually it is on the lead truck of the tender. In extreme conditions both tender trucks are used. And to please our friend Triplexer, the ultimate extreme is to place additional cylinders and drivers on the tender, making the engine a triplexer.

Trailing truck boosters seemed to be much more common then tender truck boosters. Could you please provide sources regarding the tender truck use?

Use of a trailing truck booster allowed the engine to be self contained, not requiring the need for yet another steam-tight connection between the engine and tender.

With the development of the cast delta truck frame, the booster then had a nice structurally stable frame to work from.

Tender boosters were fairly common among smaller engines that required assistance occasionally. In my HO stable I have a consolidation with a tender booster. Additionally switchers also carried booster tenders for occasional use.

I.H.B.'s U-4a class had tender boosters on the lead truck of the tender. There were actually side rods connecting the two lead tender axles outside of the truck sideframes. A good number of New York Central's engines also had booster engines. These were mostly affixed to the trailing truck of the locomotive itself. Mikados, A-1a thru A-1c class Berkshires, Hudsons and Mohawks had boosters on most.
Mike

Back to the subject.....seems the consensus is that, among the operating or operable 4-8-4s in the US that #614 wins hands down in the flat land express as well as up Sherman Hill?

Heck NO !!! Since 3751 is just about in my backyard, I'll go with the engine that is close by and personal. Besides, I got to meet the enginemen and got a chance to speak with them IN the CAB. Let's see you beat that.