Steam engine wheel arrangements...

[Anonymous]

Is there anyone out there that might be able to explain why the wheel arragements of steam engines was never standardized once the science was perfected, and the best all around arrangement and engine design settled on that worked for everything ?...
I've heard that the 4-8-4 Northern came closer to fitting this mold than any other. Is this true ?.

trainluver1

[csxengineer98]

what do you mean by standerized?
csx engineer

[PNWRMNM]

Wheel arrangements were standardized, but not much else. Part of the reason for the variety is 100 years of history. The other is that the "science" as you call it never was perfected. Most railroads both experimented and bought blocks of standardized, at least to them, power.

Mac

[Hugh Jampton]

Different types of locos for different types of turns

[tree68]

All you have to do is look at the variety of D-E locomotives currently in use (and how they are used) and you'll have your answer.

Different sizes/types of locomotives are best suited for different kinds of work. Ed probably won't be using an SD90MAC for the work he does in Houston, any more than CSXEngineer will use Green Goats for his daily mainline ride.

While some railroads found they'd made a wrong choice from time to time, they usually bought the locomotive that was best suited to the job at hand. NKP found the Berkshire a good fit for their fast freight philosophy. The 4-8-4 probably was the "ultimate" general purpose steam locomotive, but it's not the best tool for every job. The humble Mike remained a jack-of-all-trades for a long time, probably the GP-38 of its day.

[CopCarSS]

The Northern was as close to a "perfect" locomotive as was made. Lots of railroads used them for dual service, hauling a little bit of everything. But at the same time, you wouldn't want to take one on a light duty branch line. And making a Narrow Gauge Northern probably wouldn't have worked. And I doubt that it would have worked as well as a K-36 Mike up Cumbres pass. Those low drivers on the classic freight configuration were perfect for pulling in that situation. The big drivers of a Northern would have never fit under a narrow guage loco, and they would've probably been wasted (can't imagine a lot of 75 mph+ running on narrow gauge).

There were some railroads out there where 8 drivers on a rigid frame weren't enough, either. The UP (4-12-2), and Pennsy (J1 2-10-4, I1, 2-10-0, and Q2 4-4-6-4) come readily to mind. Come to think of it, did the Pennsy even have a Northern type? [?] And this was the "Standard Railroad of the World."

Chris
Denver, CO

[CSSHEGEWISCH]

PRR didn't actually have a true Northern, but the T1 could also be viewed as a divided-drive 4-8-4 since it wasn't articulated.

The closest thing to standardization that ever occurred in the steam era was the various USRA designs in the World War I period.

[oltmannd]

Basically, because you couldn't MU them!

You can have std. diesel loco designs because you can just add trailing units until you have a match for the train & route combination.

With steam, the only way to improve crew productivity was to have a more powerful locomotive.

[tree68]

QUOTE: Originally posted by oltmannd

Basically, because you couldn't MU them!

You can have std. diesel loco designs because you can just add trailing units until you have a match for the train & route combination.

With steam, the only way to improve crew productivity was to have a more powerful locomotive.

Very true. Even with the MU consideration (approximated with double- and triple-heading of steam, multiple crews notwithstanding), there are size and other factors involved, though. Weight and length have been mentioned.

[CopCarSS]

QUOTE: Originally posted by CSSHEGEWISCH

PRR didn't actually have a true Northern, but the T1 could also be viewed as a divided-drive 4-8-4 since it wasn't articulated.

The closest thing to standardization that ever occurred in the steam era was the various USRA designs in the World War I period.

That's true...The T1 was sort of a 4-8-4. Never thought about that.

Actually, I'm kind of surprised at the title of "Standard Railroad of the World." From what I've seen of the Pennsy, they were just a little bit different than most roads. When I think of Pennsy, I think of Belpaire boilers, duplexes, different wheel arrangements, etc. Stuff that really wasn't standard. I guess it probably has more to do with the fact that the Pennsy was the standard by which all other railroads were measured,

Chris
Denver, CO

[gabe]

QUOTE: Originally posted by CopCarSS

QUOTE: Originally posted by CSSHEGEWISCH

PRR didn't actually have a true Northern, but the T1 could also be viewed as a divided-drive 4-8-4 since it wasn't articulated.

The closest thing to standardization that ever occurred in the steam era was the various USRA designs in the World War I period.

That's true...The T1 was sort of a 4-8-4. Never thought about that.

Actually, I'm kind of surprised at the title of "Standard Railroad of the World." From what I've seen of the Pennsy, they were just a little bit different than most roads. When I think of Pennsy, I think of Belpaire boilers, duplexes, different wheel arrangements, etc. Stuff that really wasn't standard. I guess it probably has more to do with the fact that the Pennsy was the standard by which all other railroads were measured,

Chris
Denver, CO

Exactly.

Do you happen to remember the trains article showing a 50s Pennsy Poster with the T-1, an E unit, its steam turbine (and I think there was another locomotive) and the caption of something to the effect of what would railroading be like if the Pennsy were around today?

Gabe

[Overmod]

In a sense, there WERE standardized 'wheel arrangements' -- the USRA locomotives.

Whether or not you agree with the politics and implementation, the designs that were produced for USRA have to rank as both effective and good-looking for their day -- and they certainly seemed to hold up usefully in later years. Something I think is notable with respect to this topic: the range of standard USRA designs: perhaps the minimum that would cover anticipated services required by American railroads circa 1917.

It is, of course, possible to speculate on what a standard set of USRA designs would have looked like for the time of WWII -- probably extending the heavy Mike to 2-8-4 and establishing dual-service 4-8-4s. Woodard's application of "Super-Power" (hype or otherwise, influential in steam design) and the practical development of simple articulateds came in the 1920s, after USRA. (On the other hand, so did the wacky compounding and high-pressure stuff, in the '20s, and the divided-drive and AAR overbalance mistakes... think ACL R-1... in the '30s).

The 'killer app' for using oil-electric locomotives in mainline railroading was the adaptation of Sprague's idea on MU control effectively. (And then getting MUed power to qualify as a single locomotive for union crew purposes, regardless of net horsepower). Once you did that, it became relatively simple to have 'units' (to use GM-EMD's clever term) that would go anywhere steam could go, with less track damage etc., and generally perform better and more flexibly in most respects.

Then the great innovation: easy finance terms (taken, I believe, from GM's experience with automobile sales). Even late in the game, Baldwin and Alco failed to appreciate that even equipment trusts might approve of amortizing very 'expensive' equipment if the bottom-line revenue per dollar of capital expense could be improved.


As a note: you could make 4-8-4s quite light and still have them capable; witness the NC&StL Dixies (one is available for firsthand inspection in its new shelter in Nashville). But there were pending revolutions in suspension and guiding in the late '40s, notably Fabreeka springs, that would have made 2-wheel lead trucks capable of effective high speed equal to anything required for freight traffic... and practical passenger service on many routes. My own opinion is that six-wheel trailing trucks, even on Double-Belpaire locomotives, would have been overkill for rigid-frame locomotives... but some more advanced designs of trailing truck would have been needed to stabilize things with two axles given the long firebox/chamber profiles coming into favor with better understanding of what parts of the boiler were capable of making the most steam.

Something of potential interest in this regard: a reasonably experienced steam designer currently believes a 4-6-0 can be made to produce over 4000 effective horsepower with correct design (see www.5at.co.uk) -- there aren't too many places such a locomotive will not run...

[M636C]

While there were no "standard" locomotives in WWII, the SP GS-6 found its way to two other roads, as did the Rock Island 4-8-4 and the UP second design of "Challenger". These worked as well as any standard designs, although Rio Grande got rid of the Challengers after the war. This wasn't a worse reception than some USRA locomotives received in their time, of course.

Peter

[Anonymous]

Question about steam... when double heading how did the crews work together to keep the train moving?

[Overmod]

Peter is right about the de facto 'standardization' of locomotives around WWII. If I may suggest, a still better example of the principle might be the PRR J-1 class 2-10-4, which was essentially taken from a C&O design of the Thirties. Seems to me, though, that most of the 'standardization' actions of the war years were intended more as guaranteeing an absence of 'teething problems' and assurance of reasonable best practice, rather than providing parts interoperability across different railroads, creating a larger common installed 'base' for common parts and equipment, etc. -- the principles Dilworth et al. used so successfully in developing EMD.

There have been some very good articles on doubleheading practice (and, I believe) some good posts on the forum regarding how it was best done. I apologize in advance if any of the following doesn't apply to a particular railroad of interest. The basic principle in those days (essentially before cab-to-cab radio) involved a combination of whistle signals and 'train feel'. The crew in the leading engine normally would 'set the pace' (and, of course, were watching the signals and track, taking orders, etc., and probably controlling the train brake). They would use whistle signals to give the trailing engine crew(s) warning about starting, and when needed about stops or reductions -- I would presume each crew would have knowledge of slow orders, etc. over the route traveled.

Remember that multiple locomotives don't have to run in perfect sync to exert higher force on a train -- this may seem a bit 'counterintuitive' but it's true. I think that in steam days, there had to be a higher 'reserve' of rated power over what's currently done with MUed diesels -- in part this is because steam makes restricted and very 'peaky' power at low speed (even with small-drivered engines) -- but once up to a reasonable working speed there would be plenty of power in reserve to overcome any mismatching of developed power among the locomotives.