Granted, these engines are all gone and nobody's really debating whether to restore a huge 2-8-0/2-10-0 vs. a 4-8-4/4-6-6-4, but i thought this might be interesting, in light of the recent thread on restoring a "real" passenger engine. .



A little review:

H-9 2-8-0 No. 847 Consolidation: TE: 68,200/71500?, Driver Dia. 61" BP 210 PSI
J-1 4-8-4 No. 1410 North/Pot TE: 70,600 Driver Dia. 69" BP 255 PSI

M-2 4-6-6-4 No. 1205 Challenger: TE: 95,500, Driver Dia. 69" BP 250 PSI
I-2 2-10-0 No. 1111 Decapod: TE: 96,300 Driver Dia. 61" BP 240 PSI

A report designed to measure the performance of Wild Mary's Consolidations, Decapods, Northern/Potomac & Challenger types was prepared and issued by the WM operating department. The data was derived from tests conducted in May and June 1947 and the The report covers a myriad of information, dates,specifics of test, coal and water usage, speed, time, etc.

It was reprinted in S Kip Farrington Jr's book Railroading Coast to Coast: Riding the Locomotive Cabs Steam, Electric and Diesel 1923-1950.

However, a picture is worth a thousand words and here are the HP curves from the report. I added in blue, the class & wheel arrangement.





It appears to me that the tests resulted in the conclusion that the Consols/Nor and the Dec/Chall were alternatives (one for the other in each paring) in some respects..

In both cases the trailing truck equipped engine generally resulted in faster and more efficient service. It also indicated that the Consol was superior at very low speeds because of higher TE for the Consol the report says it was rated 900 less and 1400 less as tested-due to undersized tires on the 2-8-0. I assume that where the book indicates the Consols TE as 71,500 and not 68,000+, that is correct.

While the 4-8-4 is superior than the consol unless your are going 5 or less mph, the Decapod outpulls the challenger until 20mph. After that, hands down for both of the for trailing truck equipped engines.

My conclusion is that unless you are going to be able to run at greater than 20mph (i.e., the increasingly rare mainline service), a smaller engine without a trailing truck will do fine, or you really might be better off with a smaller freight engine than a passenger engine.

Comments?






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Boy this is going to open a can of worms and most likely step on a few toes. But so be it. A 4-8-4 might be nice,but if I'm running on Class 2 track I have wasted money that could have gone into selecting something more suited for my operational realities that can do what needs doing as economically as possible. IMHO there are several locomotives out there operational that cannot operate as efficiently as they should be because they were rebuilt because they were in that particular location and everything came together for it to happen.No thought was given as to where the locomotive would work. Since I am evaluating starting an excursion line from scratch,this is one thing I had to think about and I've settled on either a Mikado or a Consolidation. Both can handle the size trains I'm looking at( maximum eight heavyweights),the ruling grade, (1.5%), Curvature( 8 degrees) and track condition and speed (Class 2 90 lb rail.)

But were we not talking about PASSENGER power? Bring us the graph for the K2 4-6-2, and we'll talk. Granted, I haven't seen a photo of a passenger train on the WM that couldn't have probably been handled by a PRR 4-4-2, but.........

The only other curve I have digitally is the PRR T-1 from a Baldwin Magazine. I think I have one of the first LVRR 4-8-4 (about 4000HP, I think) If WM ever dyno'd their Pacific, I'd love to see it.

I have to get GIMP to scale it down to post it, but it will be similar in shape to the 4-8-4, only PRR claimed about 5000 HP.

Given the driver size of WM 4-6-2, the fast freight engines were a useful proxy for passenger engines, (although bigger). since the mechanical and performance differences between FF and P were pretty insignificant.

Interesting, to say the least. Wonder if any data still exists for those railroads that took locomotives built for passenger trains and converted them to haul freight. There were a number of examples. Including Illinois Central 4-6-2's; Monon 4-6-0's; even Burlington 4-4-2's! All of these had large drivers replaced with those of much smaller diameter. How much better were they actually in freight service? All of them would have operated at the speeds, and in the service, that nearly all museums and tourist trains operate today. Unfortunately, I can't think of one example that survived. Anybody out there got a steamer with say 79" drivers that they would like to convert to, say, something like 56"?

Les

Thought I don't claim to be an expert on the subject at hand, I would posit that the WM probably would have been just as well off to have modernized their 2-10-0 fleet and added a few more. Nowhere on the system were freight trains allowed over 50 mph, and on much of the route, freights were limited to 40 mph by topography. The run between Baltimore or Rutherford Yard in Harrisburg and Cumberland were hardly long enough for the 4-6-6-4's or 4-8-4's to stretch their legs, and west of Cumberland to Connellsville, grades, curves and bridges of the Allegheny crossing restricted speeds. According to the test data, the WM I-2 engines reached maximum hp at about 25 mph, plenty to get a train rolling and keep it moving on the WM's profile and great for slogging up the Allegheny Front. Imagine what a fleet of big Decapods with limited cutoff, cross-counterbalancing and lightweight rods might have been like!

Superheater,

From a very simplistic point of view, I think an engine with some kind of trailing truck has merit in today's environment where it is a luxury to be able to turn your power on a turntable or wye. The trailing truck will help alleviate some stress and pounding on the track structure as it helps guide the engine through curves, regardless of speed.

At WMSR, they probably have the best possible engine as it agrees with your criteria plus they turn her on both ends of the run.

Rob Gardner

Baldwin (and perhaps other manufacturers) designed some locomotives to perform as well in reverse as in forward mode. Baldwin had a series of engines they touted as "double-ended," ranging from 2-4-2 to 2-8-2. Most were utilized in logging, mining and agricultural service where turning was an unnecessary luxury. Among features of this group of locomotives were a drawbar and drawbar pocket on engine and tender engineered to alleviate potential jack-knifing. Another was the arrangement of the spring rigging on the trailing truck to steer the locomotive into a curve when operating in reverse. They were also fitted with a full-size headlight facing to the rear, usually on the tender deck but sometimes atop the cab.

Once again it is interesting to see the evidence of the dominance of diesel over steam. Those low horsepower ratings at 5 mph explain why so many helpers were eliminated with dieselization.

I suppose so, but what's the horsepower rating of an SD-45 @ 40mph?

Diesels can start trains they can't pull, steamers can pull trains they can't start. Seems like the practice of doubleheading (with steam at the head end, of course) may have some practical application after all.

Articulated power had other advantages such as a shorter rigid wheelbase, and a lighter tread than long-coupled single unit locomotives. There's more than just HP / speed curves to consider.

Still scratching my head over the light FEC pacific way up in the Rockies.......

dave

Dave -

What is really amazing is that NOT ONE of those railroads with modern steam power thought to put a box in the cab of a steamer where a single crew could control both the steamer, and a diesel (or diesels) behind when the additional T.E. was needed. It might have extended the life of some steam locomotives and, more importantly, gotten a greater return for the railroad's investment. But no one thought of it in the mad rush to dieselize. Thus expensive diesels were purchased while modern steam, still so very serviceable and in some cases, almost new, got sent to the scrap heap. No, it took a railroad years later, with a little old "tea kettle" (Clinchfield 4-6-0 #1), to finally come up with the idea!

Les

The tractive effort of the H-9 consolidations increased to 71500 when the boiler pressure was raised from 210 to 220.

The 1400's had roller bearings on all axles. That makes them the logical choice for todays mainline service. The challenger would be the engine to restore if you are just after the "wow" effect. The axle weight of the 2-8-0 is nearly the same as the 4-8-4 so it is definately not going to be an engine for a small branchline type of excursion. The decapods were great but would have little place or opportunity to run in todays world.

Perhaps the only big late model engines the WM did not use in passenger service were the 2-8-8-2's, the I-2 decapods, and the challengers. A few of every other class were equipped with steam heat and signal lines. All of the 1400's were equipped with signal and heat lines. When needed, any of the locomotives so equipped would be used in passenger service. Troup trains were frequently powered by these larger "passenger" engines.

To expand on Wayne's thinking, imagine if in 1927 Lima could have convinced WM to buy booster equipped super power 2-10-4's similar to the T&P engines. With the boosters these engines could have matched the performance of the 2-10-0's. Then instead of challengers in 1940 they had decided on 12 more improved 2-10-4s and also added the improved cast frames and roller bearings to the older group of texans. After the war they could have purchased 12 more of these imporved engines. Now they would have 44 nearly identical engines that could go anywhere and do any job on the mainline. When needed they could run 50 mph without problem. Their horsepower curve would be nearly perfect for the WM. I was convinced this may have been the best possible steam motive power development for the WM while riding behind T&P 610 on the Southern mainline at 50 MPH. It is sure an interesting concept to ponder.

As for which to restore, being an absolute lover of WM steam since childhood I say buy the railroad from Big Pool to Connellsville, restore them all, and run the hell out of them. An interesting fact, at least to me, is that I have always considered 847 in its final days to be the best looking of the H-9's. It is nice to see a favorite on the chart.

John Bohon

The question is why would you do it now and I would think it would be hugely expensive over and above a usual overhaul. If one was extant it would be an interesting beast.
As an aside,some passenger power did run on freights without modification. I still have my uncle's timebooks from the Santa Fe where 1309 class Pacifics were marked up for local freight service as late as 1954

Here's the HP curve as provided by the Baldwin Locomotive Works 1945 Article. The same basic shape as the WM 4-8-4 applies, but with peak power coming at about 70MPH. Surely, the WM 4-6-2 smaller drivers made peak power @ a lower speed, but can we assume peak power will come @ at LEAST 40MPH?