Western Railroad Discussion > So what was the most powerful steam locomotive?

So what was the most powerful steam locomotive ever built...if you go by horsepower ratings? From what I've found out so far Pennsy's Q2 had the most horsepower of any steam locomotive (I've listed the locomotives that I know the horsepower ratings to). Also what where the horsepower ratings on some of the other big locos that I didn't metion below.

PRR Q2=8000hp
UP Big Boy=6300hp
N&W Y6b=6300hp

Kyle

What About the C&O 2-6+6-6???

CR4114 Wrote:
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> So what was the most powerful steam locomotive ever built...if you go by horsepower ratings? From
> what I've found out so far Pennsy's Q2 had the most horsepower of any steam locomotive (I've
> listed the locomotives that I know the horsepower ratings to). Also what where the horsepower
> ratings on some of the other big locos that I didn't metion below.
>
> PRR Q2=8000hp
> UP Big Boy=6300hp
> N&W Y6b=6300hp
>
> Kyle

See the article "Big Boy or Big Mistake" in this month's Trains. Mostly, the author rags on the fact that most of the high horsepower steam locomotives rarely were able to use their full power as the peak power occured at speeds that they did not operate at. This is unlike a diesel electric where the full power can be used at any speed over about 12 mph (exact number depends on the power, number of axles, weight on the axles, etc). Below that and you have wheel slip.

Anyway, he lists the N&W A with 6300 HP, the Union Pacific Big Boy with 6300 and the C&O Allegeny with 7498. I had thought that the Allengeny with about 7500 HP was the most powerful reciprocating steam locomotive. To a great extent the horsepower depended on the boiler capacity and the ability of the locomotive to run at a relatively high speed (power = traction effort X speed). Are you sure it is the N&W Y6b and not the A with 6300 HP? The other locomotive that may have been the most powerful was the Pennsylvania S1 6-4-4-6 as it had a huge boiler and would run well over 100 mph. I am faily sure the Sante Fe 2-10-4s were the most powerful simple engine (non-articulated and non-duplex) built.

I don't know its HP, but in terms of TE, the most powerful must have been either the VGN 2-10+10-2 or the N&W Y6B.

Although not a rod-driven engine, but still a steamer, N&W's "Jawn Henry" could ring up about 200,000 lbs. of starting t.e.

From SteamLocomotive.com


Most Powerful

DBHP: Drawbar Horsepower
IHP: Indicated Horsepower at cylinders
CHP: Calculated Horsepower

PRR Q-2 4-4-6-4 7,987@57.4 (IHP)
C&O H-8 2-6-6-6 7,500@40MPH
PRR S-1 6-4-4-6 7200 (DBHP)
PRR S-2 6-8-6 6,900 (IHP)
NYC S-1-b 4-8-4 6,680 (IHP) 5,070@85mph (DBHP)
WM M-2 4-6-6-4 6,345
DM&IR M-4 2-8-8-4 6,250
PRR T1 4-4-4-4 6,110@85.5MPH (DBHP) 6,552@85.5MPH (IHP) (w/o tender)
SP AC-12 4-8-8-2 6,000@40MPH
UP 4-8-8-4 6,200 (DBHP) 6,000@37MPH (CHP)
C&O M-1 4-8-0-4-8-4 6,000 (turbine) 3,000 (DBHP)
N&W Y6b 2-8-8-2 5,600@25MPH (simple expansion mode, with booster)
SP GS-4 4-8-4 5,500@55MPH (DBHP)
N&W A 2-6-6-4 5,300@43MPH (DBHP) 6,800@38MPH (IHP)
N&W J 4-8-4 5,300@40MPH (DBHP)6,000 (IHP)
AT&SF Madam Queen 2-10-4 5 ,000 (DBHP)
UP 4-12-2 4,750 (IHP)


Most Pulling Force

N&W Jawn Henry C+C+C+C 180,000 lbs. Tractive Effort
Virginian X-A 2-8-8-8-4 166,300 (compound) 199,560 (simple)
Virginian AE 2-10-10-2 147,200 (compound) 176,600 (simple)
N&W Y6b 2-8-8-2 170,000 (simple expansion mode, with booster)
Erie P-1 2-8-8-8-2 160,000
GN R-2 2-8-8-2 153,000
N&W Y6b 2-8-8-2 152,206 (simple expansion mode, before mid-1950 modifications)
WP M-137/151 2-8-8-2 151,000 (with Franklin trailing truck booster) 137,000 (without booster)
DM&IR M-4 2-8-8-4 140,000
UP 4-8-8-4 135,375

zephyrus Wrote:
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> From SteamLocomotive.com
>
>
> Most Powerful
>

> PRR Q-2 4-4-6-4 7,987@57.4 (IHP)

Definetely the winner. I had always thought that the C&O 2-6-6-6 was the most powerful. I have to add that I am still disgusted that the Pennsylvania scrapped almost every locomotive that they built. There are no duplex locomotive that did not get scrapped. They could have donated at least one T-1 to a museum and the Q-2 was certainly one of the more interesting locomotives built.

> AT&SF Madam Queen 2-10-4 5 ,000 (DBHP)

I believe that the later 5001 and 5011 series 2-10-4s had more power as they had more steam pressure and larger drivers but it is not listed in your source. However, they have a lot of interesting information.

The 5001 and 5011 with higher pressure and larger drivers probably had a power curve that enabled them to pull more at higher speeds. The brute drag freight articulates might have been able to start more but they likely had effective top speeds below 20 mph. Like wise the Big Boys probably had better high speed performance than the engines designed to drag bulk cola or iron ore.

quote shaamelessly cut and pasted
The 'Q2' was indeed a formidable machine. One of the class developing almost 8000 indicated horsepower under test, the Pennsy had all twenty six locomotives in service by 1946 and their ability to highball very heavy freight loadings became legendary. Advantages when compared with conventional locomotives included reduction of revolving and reciprocating parts, less mechanical friction, shorter stroke and improved cylinder performance at high speed. A significant difficulty encountered with the T1's was the tendency to go into almost uncontrollable wheel-slip, even at high speed, a problem overcome in the Q2's with the application of an electrically controlled automatic anti-slip device. Unfortunately the Q2's suffered in route availability because of their higher than usual axle loadings. This factor coupled with various maintenance problems and the ability of the other PRR large freight locomotive, the 'J1' 2-10-4, to operate over much more territory, together with the oncoming diesel stampede conspired to see them all retired by 1952.



Wonder what they did under their standard operating conditions as far as actual horsepower. Optimized testing not withstanding. Appears they had limited areas of service between axle loading and their minimum radius with the rigid frame.

Anybody have the figures for the SP and UP 4-10-2s? What was their hp/ton. 3 cylinders on 5 driving axles, the Q-2 had 4 on 5 axles.

Sounds like the Q's were like the piston propellor aircraft coming out at the same time, last gasps to use a dying technology by non-believers when the new technology had already passed by. (Many many years ago Trains ran a series of articles by some of the men who introduced and/or the first diesels on several of the big RRs. UP and Pennsy were two articles. the Pennsy guy recalled that they initially put the diesels on a maintenance routine like big steam as far as back to the roundhouse for inspection and repairs, etc. Once they realized it didn't need the maintenance, they started using for longer periods, then they noticed wheel wear and figured that they were doing something wrong or the wheels were faulty. Checked the records and found they had put on almost 10 times as much miles as a steam engine in the same time period and something like 3 times the mileage to get the similar wear. the motive power heads just didn't want to believe the diesels could do it.)

See the Eastern Board for some more comments on this topic. BTW, the PRR Q-2 did not best the C&O H-8, as the Q's figure was IHP, while the H-8's was DBHP actually registered while pulling a coal train.

NYCSTL8 Wrote:
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> See the Eastern Board for some more comments on this topic. BTW, the PRR Q-2 did not best the
> C&O H-8, as the Q's figure was IHP, while the H-8's was DBHP actually registered while pulling a
> coal train.

I missed that. Definitly want to go with the drawbar horsepower. I thaought that maybe the Q-2 managed to do better as it may have had poppet valves which were more effecient at higher speeds. I know the T-1s had poppet valves but I am not sure about the Q-2s. Anyway, they would not compete with the diesels which ran well under all conditions.

Ed_Gyptian Wrote:
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> Sounds like the Q's were like the piston propellor aircraft coming out at the same time, last gasps
> to use a dying technology by non-believers when the new technology had already passed by. (Many
> many years ago Trains ran a series of articles by some of the men who introduced and/or the first
> diesels on several of the big RRs. UP and Pennsy were two articles. the Pennsy guy recalled that
> they initially put the diesels on a maintenance routine like big steam as far as back to the
> roundhouse for inspection and repairs, etc. Once they realized it didn't need the maintenance, they
> started using for longer periods, then they noticed wheel wear and figured that they were
> doing something wrong or the wheels were faulty. Checked the records and found they had put on
> almost 10 times as much miles as a steam engine in the same time period and something like 3 times
> the mileage to get the similar wear. the motive power heads just didn't want to believe the
> diesels could do it.)

I remember the article. It was the kiss of death for steam as a few EMD passenger locomotives were doing more useful work than the whole fleet of T-1s. Maybe a better comparison would have been with the NYC Niagaras which probably required less mainenance than the T-1s but they also went to an early death. The NYC was not much better the Pennsy and scrapped them all up. I would have been nice to have a few of the latest and greatest left for future generations to look at.

The PRR Q-2 did not have poppets. And, from what I have read, the unique anti-slip devices did not work very well, maybe partly because roundhouse forces did not maintain them consistently. As an aside, the Q would have benefited from the use of an N&W-style "canteen," as the water stops put the big duplexes at a disadvantage against the diesels. As for the PRR not saving any duplexes, I think the reason must have been that these locos had not worked out well at all, so saving an example would have been a constant reminder of that. None of the J-1's was saved either, presumably because it was not a Pennsy design, having been copied from C&O's Lima T-1 during WWII. The NYC Niagara was a far better loco than the PRR T-1, but the Central already had E-7's on the "Century" before the Niagaras were delivered, so these engines were doomed from the beginning, despite their capabilities. The Central's attitude re: saving steam power was the same as N&W's after Mr. Saunders took over: bury the past, to hell with history and tradition. Winston Link got Roanoke to save 611, but no such savior appeared for a Niagara.