NW-Y6a- #2156 STATUS UPDATES?

Trains Magazine Steam & Preservation
21

I think the Y6 was a fairly misunderstood engine - Why would anyone try to improve a COMPOUND locomotive in 1957? The compound idea was on the whole was about economy almost more than pulling power.

Lets go back to basics - the steam railroad locomotive was a different power compared with stationary power plants and with marine power plants in one major design criteria. It was designed to generate the maximum power attainable in the smallest design package and to generate that power quickly. To do this the efficiencies of the marine power and stationary power were compromised.

The railroad locomotive used a small “horizontal high draft boiler” that often failed to burn fuel economically. It is a known fact that much of the coal burned under load was consumed before it even landed on the grates and much of it went out the smoke stack as unused carbon and unused fuel gasses. In design reality, it was a constant battle to get the heat (BTUs and calories) out of the fuel and get usable work out of it quickly. This was the idea behind the firebox brick arch and combustion chamber. New ideas of air delivery to the grate were never fully developed.

Also in persuit of usable steam power was the increase in boiler pressure, to as high a practical limit as possible without increasing the structrural weight and mass of the boiler. Also to make the locomotive boiler repairable without undue maintaince complication. With operating pressures between 200 and 300 psi this was a practical reality. Also the addition of steam superheat design to boiler flues in the 1920’s became the truely significant power producing technology of the super power era of the 1920’s. Feed water heating was another power and economy technology perfected in the super power era.

Other paths of economy tried before super power - compounding was tried in the early 1900s. All this was done remember in an effort to improve loco

22

Folks, NO NO NO there was no “actual” Y6c class on the N&W, once again my post has been misread. There was however an experiment on “one” Y6b that yielded dramatic power gains.

Since this “one” Y6b would be a standout to other Y6b’s, how would you differentiate between them? Well, you give them a new class. This is how railroads did it. Even N&W!

It would NEVER be “Y6b improved” as railroads classed their locos with letters and numbers, not full words. This is why you always see “K4”, “S1”, and even “Y6b”. Heck, “Y6b improved” wouldnt even fit on the blueprint legend. Top of the page maybe. But no one ever classed a loco with the words “improved”. Show me, and I will stand corrected.

Dont forget to take into account, where did the “b” come from in the first place?

Rest assured, the Y6"c" designation is only a reference to the one Y6b that got this upgrade, not its actual class designation. It is for ‘our’ purposes only.

I have no clue why the name Messena keeps coming up as he isnt the first one to use the Y6"c" designation. The retired N&W loco engineer I got this info from never heard of Messena, but did know about the Y6"c" test loco and also the Y7 class. He operated many Y6, and A’s before retirement. Since the test loco was never further developed, even he didnt know which designation the loco would have finally gotten, if built (or rebuilt, in the case of existing Y6b’s).

Had diesels not prevailed, there is no doubt N&W would have built a new class, and that would be the Y7. Being built with the new mods, and being “rebuilt” with the new mods is two totally different things. Thus, two totally different class designations.

Had all the existing Y6b’s been updated, more than likely N&W would have gone with Y

23

One more thing, had this upgrade on the Y6c been added to other N&W locos, dont think for a minute other railroads wouldnt have copied it.

Thus, when given to a Big Boy, the Y6"c" would again pale in comparison. And we are back to square one. Horsepower wars didnt start with the diesel!

24

As a historical reference, by the time that N&W had proposed these various upgrades, the rest of railroading in the United States was firmly committed to the diesel.

25

PM Railfan,
I have no idea where you are getting your information from, but, you have your facts all confused on this Y6c deal. You say that Messena has nothing to do with it, yet, what you are saying is reading almost word for word exactly like Messena wrote in his articles.

Go read the book “Rails Remembered Vol. 3” by Louis M. Newton. He had first hand experiance to these tests and set all of the facts straight.

On the “Improved” deal. Yes, N&W posted right there in the employee timetables figures for the Y5 & Y6 “Improved”. “Improved” meant that the locos were equiped with the “External Reducing Valve” and booster. This gave the Y6 more power and caused them to add lead weight to the front engine frame in order to stem the slipping that this initially caused. The “I” rating (this how it is stipulated in the ETT, Y5"I", Y6"I", etc.) brought with it tonnage ratings higher than unimproved locos (no “I”).

Once all of the bugs were worked out of the “ERV&B”, performance was “improved” so much that they decided to add the “ERV&B” to the entire Y5 - Y6b classes. This created a fleet of 100 “Improved” Y class locomotives. And whether it was a Y5 - Y6 - Y6a or Y6b, they were all rated the same for the specific district they were operating on (each distict having its own tonnage ratings account of grade differencials). But you can learn all about this in Bud Jeffries book “N&W Giant of Steam - Revised Ed.”.

Although written specificaly about the C&O H8 2-6-6-6, N&W Class A 2-6-6-4 & UP Big Boy 4-8-8-4, the Y6 class also merits its own chapter in Eugene Huddleston’s book “World’s Greatest Steam Locomotives”.

I would strongly suggest that you take the time to read the above books in order to learn the true facts about the Y class locomotives.

Another point someone

26

Thanks, Big Jim for your comments. It may be just me, but i have been interesting in the N&W steam program for a long time. I had read of it as if seemed to be wirtten about as if it were a step child to the PRR Steam. Obviously, it was definitely not that, but was an innovative and progressive program.

Many around here may not know who Robert A Le Massena (1914 to 2013) was, and his status as a contributor to TRAINS magazines; and author of at least 18 books on railroad subjects and locomotives.

The most complete biography seems to becontained in his obituary: Linked @ http://www.foothillsfuneral.com/fh/obituaries/obituary.cfm?o_id=2312572

The following linked site[steam locomotives.com] contains much information on N&W steam engines, see link @ http://www.steamlocomotive.com/2-6-6-4/?page=nw

Specifically, a number of ‘hot links’ at the bottom of the page should interest readers of this Thread.

Still hoping that anyone can advise us when the N&W 2156 is on the move, from MoT to Roanoke.

27

Sam,
Someone in the N&W HS very close to St. Louis is keeping an eye out for movement and will let the rest of us know. It would imagine there will be some media publicity about it too. Patiently awaiting the return myself.

28

I can only give my own opinion. There was no such thing as a Y6c except in LeMassena’s imagination. Please read the following four articles if you must argue that a Y6c existed in any form whatsoever, even as a one-off:

Nov 1991 Trains, pgs 64-69
May 1992 Trains, pgs 64-68
May/June 1994 Arrow (NWHS), pgs 14-17
Jan/Feb 1998 Arrow (NWHS), pgs 14-18

To reiterate (and yes, some of this is self-serving) read the initial article in Nov 1991 Trains, the rebuttal of Louis Newton in May 1992 Trains (only a partial was published, he submitted a lot more than was printed), his full rebuttal in the May/June 1994 issue of NWHS magazine The Arrow and my article in the Jan/Feb 1998 issue of The Arrow.

The initial article contains many errors of fact, some of them substantial. N&W did not modify the Y6b involved in the 1952 steam vs diesel tests. Why?? Because they didn’t have to. The performance it turned in was well within its capabilities without modification. Trains made a major misstep in printing that article without (apparently) checking with a credible N&W source, NWHS for one, that was available at the time.

Keep in mind that duing the 1950s, N&W was implementing the system-wide use of auxiliary water tenders, an operations change which increased train tonnage and reduced running time.

There were several other changes occurring simultaneously, all of which increased gross ton-miles significantly. However, the increases had nothing to do with altering the basic design of the Y6’s.

Let’s remember one thing. N&W was in business to make money. Sure, company pride existed when the steam vs diesel tests were run. But EMD had a reason to hot rod the F7’s (if, in fact, they did), i.e., cracking the last large market for its product. On the other hand, N&W had no economic incentive to go out and “beat the diesel” because it wasn’t selling anythin

29

Thanks ! Big Jim, [tup][tup]

I just did not want this one to’ slip past us’. Never got to see any of the Y’s work in freight service, except on some videos. I did get to see the #1218, in and around the Birtmingham area…Too long ago.

It was a very impressive machine.

30

BigJim:

“Improved” meant that the locos were equiped with the “External Reducing Valve” and booster."

By “booster” are you referring to the injection of some high-pressure, high-temp steam into the low-pressure steam? The Y’s never had booster engines, did they? Or is this something else?

31

This sounds more like you’re asking about a starting valve, which performed that function to aid in starting a train from a standstill.

32

Compounds are designed so that, ideally, the torque produced by the HP engine and that produced by the LP engine are either roughly equal or proportional to the relative adhesion limits of the two engines. In practice, effects such as heat loss result in the LP engine developing substantially less than expected. The booster valve ‘boosts’ the power of the LP engine by adding an amount of live steam that brings the average pressure at either the receiver or the LP steam chests up to ‘spec’ – or, if a bit more power is desired, beyond that… but not up to the ‘full pressure’ used when the conventional simpling valve is used.

As noted, the way the N&W had this set up, the power from the forward (LP) engine was higher enough that a bit of ballasting could provide a higher effective TE at the speeds where the booster was found most effective (IIRC from Rails Remembered vol 3 this was around 26mph).

Another way, in principle, that the ‘boosting’ can be done is to modulate steam into the LP chests more directly, so that not only the average pressure but the developed torque relative to stroke are similar between the HP and LP engines. This (in theory) allows the LP engine to be balanced accurately, and the engine to work compound to a higher speed. While it might be uneconomical to work even an ‘improved’ Y6b as fast as 40-45 mph (assuming you could get it that fast without bad riding), a modulated-admission locomotive – with, perhaps, the slight additional improvements of having its forward engine hinged only in the horizontal plane, as the Alco Challengers were famously built (and, before them, the class A

33

I think that would be the function of the intercepting/reducing valve. I remember reading (it may have been in something written by (horrors!) LaMessena.) that they added this feature that injected a small amount of high-pressure steam into the low-pressure side to boost power to the low-pressure cylinders. This could be done after it was running in compound mode.

34

Thanks, Overmod. I was still making my last response when you entered yours.

35

Paul,
Yes, the so-called “Booster” allowed a bit of live steam to enter the reciever pipe while still working in compound. It is not so much the pressure, but, the added heat that made the difference. This all worked through the reducing valve, which was now located outside of its previous location in the high pressure cylinder saddle to a position over top of the right high pressure cylinder. It is easily seen in photos of the right of the locomotives.

All steam to the low pressure cylinders was either routed through the reducing valve or from the HP exhaust to the reviever pipe going to the LP cylinders. The full 300 psi steam never went to the LP cylinders. The reducing valve regulated the steam pressure down to a value that would give the LP cylinders roughly the same power as the HP cylinders. I don’t have the exact figure at my finger tips, but, I am thinking that it wouldn’t be more than 115 - 120 psi.

FWIW, an engineer that I worked with when asked, said that 63mph was about as fast as you wanted to run one. After that, things started to get a little shakey.

36

Thanks, BigJim. And I’m wondering under what circumstances someone ran a Y at 63 mph. I think of them as low-speed tractors that could out-pull anybody else.

37

Well, some engineers on the Shenandoah Valley and Bristol line knew how to let 'em roll.

38

I wonder what the M/W department thought of those engineers. [:-^]

39

When people say the BB could out pull the Y6 and the the tonnage rating were higher for the BB you have to consider the track profile. If N&W ran steeper grades that would affect the tonnage rating. I beleave if you ran both engines on steep grades with the heaviest train that could be pulled with out stalling, than the Y6 would win,it had more TE and smaller drivers that allowed to make its HP at slower speeds. Ed king wrote some years ago that if a steam locomotive needs to be going 40 + mph to reach its max HP but is used as a drag engine running 20 mph it would have much derated HP. Also if we are talking about how mush tonnage could be started and pulled than I also beleave the Y6 would win.