Was Re: Roller Bearings and the Y6-b, Now Y6b Development

NW Mailing List nw-mailing-list at nwhs.org
Wed Oct 16 09:24:58 EDT 2019

John -

Well, let’s look at the physical limitations.  The N&W’s standard turntable
was 115 feet.  The A overhung it on both ends.  The original1910 Mallets
(the X-1 0-8-8-0s and Y-1 2-8-8-2s) had low-pressure cylinders of 39 inch
diameter.  This was the largest that would fit N&W’s clearances, which is
why the 2100s LP cylinders were 39 inches.

The proposal was that the engine would be as fast as the A but have the
power of a Y-6.  The power requirements would neccessitate sixteen driving
wheels and the speed requirements would necessitate drivers of at least 68
inch diameters.  Now, UP’s Big Boy had 68 inch drivers and it took a 130
foot turntable, even using the Centipede tender which was shorter and
higher than a normal tender.

I don’t doubt that they could have created a compound that could run that
fast; the 2100s under throttle could run 45 to 50 (unofficial reports had
them running faster than that).  But the 39 inch LP cylinder limit would
still apply, and they would have had to lengthen every turntable on the
system to handle such an engine.

Now, I don’thave any hard data supporting my position; I do know what their
parameters would have to have been, and I don’t believe they could have
made such an engine work.  If you look at what they had to do to make a Y-7
fit a 115-foot table (they had to move the boiler forward on the frame to
shorten the engine, which caused more front end overhang on curves) with
the proposed 63-inch drivers, it becomes more apparent that the proposed
A-Y combo would have have whit I believe to be unsurmountable problems.

- Ed King

*From:* NW Mailing List
*Sent:* Tuesday, October 15, 2019 11:01 PM
*To:* List NWHS
*Subject:* Re: Was Re: Roller Bearings and the Y6-b, Now Y6b Development

Do you have any data or information to back up your doubt or show why a
faster Y would need to be any longer than a Y5 or Y6?  Or run up against
the physical limitations of the N&W?  As to why N&W would want to speed up
the Y class, it would me to increase profitability and return on investment.

I understand your concern but the railroad industry determined that about
90% of the maintenance cost of the average steam engine was boiler
related.  N&W built engines with cast frames and roller bearings so the
added machinery maintenance would likely have been a low percentage of
total maintenance costs and not a big deal.

John Rhodes

On Tue, Oct 15, 2019, 6:49 AM NW Mailing List <nw-mailing-list at nwhs.org>

> John -
> If it was possible to design a 16-drivered compound that would run as fast
> as the A, which I doubt, given N&W’s phusical limitations (I doubt if they
> could have gotten such an engine on a 115’ turntable for one thing, boiler
> overhang at the front and rear-end overhang at the other end would have
> been monstrous) why would they have wanted to?  Data have come to light
> that even the Y-7 might have had difficulties there.  Gurdon McGavock was
> said to have expressed concerns about those very items.
> N&W had its bases covered with the 2100s and the As.  Their results speak
> for themseoves.
> - Ed King
> *From:* NW Mailing List
> *Sent:* Monday, October 14, 2019 2:44 PM
> *To:* List NWHS
> *Subject:* Re: Was Re: Roller Bearings and the Y6-b, Now Y6b Development
> Ed you are misunderstanding what I am saying.  I  am not talking about the
> Y7.  N&W could have built a compound Y that could have been just as fast
> and powerful as the A without being overly complex.  It should have helped
> them financially and operationally to not have 2 different road freight
> locomotives.
> John Rhodes
> On Mon, Oct 14, 2019, 11:49 AM NW Mailing List <nw-mailing-list at nwhs.org>
> wrote:
>> The point was that N&W’s financial results using its steam locomotives
>> were refined to the point that any thoughts of working around the margins
>> would probably produce minuscule results.  It was probably a good thing
>> that the Y-7 was never built.  It turned out that the Y-6 would run fast
>> enough (far faster than anyone else’s Mallets, but that’s another story)
>> for those territories where the Y-7 might have worked well.  And the Y-6
>> retained the economy of the compound.
>> The argument has been made that N&W had too many A’s, but, again, what
>> would be the benefit?  It’s arguable that they built too many S-1a engines,
>> too, but again . . .
>> - Ed King
>> *From:* NW Mailing List
>> *Sent:* Sunday, October 13, 2019 8:32 PM
>> *To:* NW Mailing List
>> *Subject:* Re: Was Re: Roller Bearings and the Y6-b, Now Y6b Development
>> The N&W did a great job and I am not trying to cast dispersion on them.
>> I am not trying to nit-pick them, I am trying to think about what if.  But
>> it is interesting to think about what the result would have been if coal
>> trains on the Kenova and Columbus Districts and east of Roanoke were
>> operated with improved Y engines that had equal speed capability as the
>> A's.  Would it have improved locomotive utilization to the point to have
>> increased N&W's profitability?
>> John Rhodes
>> On Sun, Oct 13, 2019 at 7:24 PM NW Mailing List <nw-mailing-list at nwhs.org>
>> wrote:
>>> I find it difficult to second-guess N&W’s motive power decisions in the
>>> 1950s.  For the all-steam part of that decade they were carrying gross
>>> income over to net at a rate that was the envy of the industry while
>>> handling a low-revenue commodity .  They were sparring with the mighty
>>> Union Pacific for the top spot in gross ton miles per train hour.  If
>>> people want to nit-pick their decisions, they’ll have to come upwith some
>>> very impressive facts that nobody else ever thought of to prove their
>>> points.  A case could be made that coal trains on the Kenova and Columbus
>>> Districts and east of Roanoke  could have been handled more economically
>>> with Y engines, but it couldn’t have been handless as fast, and locomotive
>>> utilization might have suffered.
>>> So I, for one, am content to enjoy what they did do rather than try to
>>> think up things I think they should have done.  Wnen I hired out on N&W in
>>> 1959 they were paying a $6.50 dividend on their common stock, the highest
>>> on the nYSE.
>>> - Ed King
>>> *From:* NW Mailing List
>>> *Sent:* Saturday, October 12, 2019 8:32 PM
>>> *To:* List NWHS
>>> *Subject:* Re: Was Re: Roller Bearings and the Y6-b, Now Y6b Development
>>> So no opinions on what the result on N&W's operations would be if they
>>> had one loco instead of having to use both A's and Y's?
>>> John Rhodes
>>> On Thu, Oct 10, 2019, 12:19 PM NW Mailing List <nw-mailing-list at nwhs.org>
>>> wrote:
>>>> All,
>>>> N&W instead of expanding the speed capability of the Y Class they
>>>> created the A Class to take care of Fast Freight, flatter districts and the
>>>> occasional heavy passenger train.  Later they realized that a single engine
>>>> type to do all freight jobs would be better for the railroad operationally
>>>> and financially.  N&W started investigating the Y7 for this role, assuming
>>>> larger drivers and abandoning compound operation was necessary to meet the
>>>> objective of a general purpose freight locomotive.
>>>> I propose that in about 1930, N&W could have sped up the compound 58"
>>>> drivered Y Class to allow it to also do everything that the Class A did as
>>>> well so that the Class A would have never been designed or built.
>>>> There are 2 issues to a Y class doing the work of an A. 1. Maximum
>>>> speed and 2. Drop off of drawbar pull at higher speed.
>>>> With respect to 1. The size of the low pressure cylinders and lack of
>>>> ability to balance them for 70 mph is the issue. Dividing the 2 huge lp
>>>> cylinders into 3 reasonable sized lp cylinders on 120 degree separation
>>>> would likely have allowed 70 mph balancing.
>>>> Also the volume of the lp cylinders is driven by the volume of the hp
>>>> cylinders. The hp cylinders size on the Y class is driven by tractive
>>>> effort requirements for the 4 axles of the hp engine.  The lp engine due to
>>>> size and the starting valve has no issue producing as much tractive effort
>>>> as needed. Changing the wheel arrangement to 2-10-6-4 would have helped in
>>>> allowing smaller hp and lp cylinders and balancing while keep TE high.
>>>> Also the 3 cylinder  lp engine with less torque variation in a rotation
>>>> should allow the lp engine to produce 25000 pounds of TE per axle vs 20000.
>>>> So a 3 lp cylider Y class should have been capable of 180000 to 185000
>>>> pounds of TE versus 160000ish pounds of rating TE for a Y5 Y6.
>>>> The second issue is drop of of drawbar pull at higher speed.  This is
>>>> an issue of steam flow and pressure drops. A 3 cylinder lp engine and also
>>>> reducing the cylinder sizes in general will help this tremendously.  But
>>>> having 2 piston valves per cylinder with the longest practical travel lap
>>>> and lead will greatly improve middle range and top end power without
>>>> hurting the low end.  High lead in valve gears can make a locomotive
>>>> slippery at low speed so variable lead based on cutoff like DRGW did would
>>>> be appropriate based on what the N&W did with the Y Class.
>>>> The live and intermediate steam piping from the dome through the
>>>> superheater throttle  and cylinder steam ports should have cross section of
>>>> 25% of the cylinder faces not 8-10% on the Y class.
>>>> Also the Y class need more  steam chest volume about 125% of the
>>>> cylinder volume.
>>>> More superheat like 850 degrees Farenheit would have helped but
>>>> probably required saturated steam cooling of the valve liners.
>>>> Also resuperheating of the exhaust steam to the lp engine would help.
>>>> More feedwater heat extraction using a 2 stage setup with open and closed
>>>> type stages. Basically adding a 2nd shell and tube stage to a Worthington
>>>> FWH would work.
>>>> When finished with this you would end up with a loco of similar weight
>>>> and size but have 70 mph top speed 185000 pounds TE and likely 7000 drawbar
>>>> horsepower on the same coal and water consumption as a Y.
>>>> And in the end Stuart Saunders would have dieselized anyway.
>>>> John Rhodes
>>>> On Thu, Oct 10, 2019 at 8:10 AM NW Mailing List via NW-Mailing-List <
>>>> nw-mailing-list at nwhs.org> wrote:
>>>>> I'd like to throw another possible reason - roller bearing rods have
>>>>> large hubs and may have interfered with the clearance limits on  the lower
>>>>> part of the N&W's load gauge.  With the Y6's 58" drivers and 32" stroke,
>>>>> there's not a lot of room  for a roller bearing rod hub.  IIRC, load gauge
>>>>> interference was a problem with the P&LE's 2-8-4's and they had
>>>>> conventional solid bearing rods and 63" drivers.
>>>>> Dave Stephenson
>>>>> On Wednesday, October 9, 2019, 9:58:26 PM EDT, NW Mailing List <
>>>>> nw-mailing-list at nwhs.org> wrote:
>>>>> Bill
>>>>>       If you’re a Trainorders member (I am not)you can go back and
>>>>> read Wes Camp’s writing on this subject recently . Very interesting  There
>>>>> were
>>>>> a lot of reasons why probably it never happened .
>>>>> Larry Evans
>>>>> _______________________________________
>>>>> NW-Mailing-List at nwhs.org
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