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PRR S1 Preliminary Designs

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PRR S1 Preliminary Designs
Posted by L-105 on Sunday, May 21, 2023 12:55 PM

Does anyone know of any books or other resources which cover the preliminary design stages of the PRR S1 between Baldwin and the Pennsylvania Railroad of 1936-1937 in detail? 

Items such as locomotive diagrams or just more detailed descriptions of the designs presented? Or are these lost to history along with the rest of the Baldwin Locomotive Works stuff from the 1930s and 40s that’s not in the DeGolyer library?

What sparked my curiosity is that in the Wikipedia article on the S1, some brief statements are made:

A conference was held between Baldwin Locomotive Works officials and W. F. Kiesel, J. V. B. Duer and W. R. Elsey for PRR, where PRR demanded a passenger locomotive to haul 15 standard cars at 100 mph on level track between Paoli and Chicago. Baldwin presented several 4-8-4 and 4-4-4-4 designs made for other railroads. However, PRR rejected the 4-8-4 design in favor of a rigid frame duplex and asked Baldwin to consider the wheel arrangement 4-4-6-4. In July 1936, PRR requested Baldwin Locomotive Works to submit a design for a 4-8-4 engine capable of handling a 2,000-ton train between Colehour and Harsimus Cove

Two months after the conference, Baldwin Locomotive Works officials presented four designs to PRR:

  • a 4-4-4-4 passenger locomotive that could haul 1,200 tons but exceeded existing weight and clearance restrictions
  • a 4-4-4-6 passenger locomotive that could haul 1,200 tons but also exceeded limits
  • a 4-8-4 freight locomotive with the same weight on drivers as an M1a, which failed to meet the requirements for a 2,000-ton train
  • an articulated 4-6-6-4 locomotive

PRR preferred 4-4-4-4 and asked Baldwin to consider a passenger version with 6 ft 8 in drivers and a freight version with 6 ft drivers

Interesting the array of duplex wheel arrangement configurations that were being discussed/designed behind the scenes already by this time. Particularly of interest for me would the designs that were rejected for being “too big”.

The only thing I have been able to find is descriptions of records of preliminary designs from the Lima Locomotive Works archives that are held at the California State Railroad Museum Library https://csrm.andornot.com/, in particular:

  • 6-4-4-6 design dated Aug 11, 1937.
  • Another 6-4-4-6 design dated Aug 17, 1937
  • A possible 4-4-4-4 or 4-4-4-6 design dated Feb 3, 1937

I am only aware of the record names however, and I have never actually seen any of them as you would need to live in the USA or physically visit the museum to get them.

Not related to the S1 but interestingly there is also a 2-6-6-6 preliminary design from as far back as Sep 10, 1929 and a 2-10-6 from Oct 24, 1925.

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Posted by Overmod on Sunday, May 21, 2023 7:19 PM

Stuff is getting commingled here.  Your very best bet is to get access permission at the Hagley in Delaware, and spend a few happy days going through the PRR motive power records preserved there.  A great many of your questions probably have direct, if presently somewhat uncatalogued, answers there.

L-105
“A conference was held between Baldwin Locomotive Works officials and W. F. Kiesel, J. V. B. Duer and W. R. Elsey for PRR, where PRR demanded a passenger locomotive to haul 15 standard cars at 100 mph on level track between Paoli and Chicago. Baldwin presented several 4-8-4 and 4-4-4-4 designs made for other railroads. However, PRR rejected the 4-8-4 design in favor of a rigid frame duplex and asked Baldwin to consider the wheel arrangement 4-4-6-4.
I suspect this has been garbled in typical Wiki fashion.  The original locomotive request as I recall it was 1000t of consist at peak speed of 100mph, which at the time (before the demonstration of Timken thin-section roller rods about 1936) was thought to involve 84" drivers.  I do not know of any version of this engine that would use a rigid coupled wheelbase; this was from what I have read over the years going to be a 4-4-4-4 following the general layout Baldwin was proposing by 1933 (which had the cylinders at the corners, like the B&O 5600 or the ATSF 6-4-4-4) and I do not think originally there was any intent of making a long and heavy 6-4-4-6 for the desired performance.  

What you will find is that Baldwin did an enormous amount of 'research' on duplex power on PRR's dime... or, more like, PRR's millions.  There is complaining correspondence (I don't remember who wrote to whom in the PRR organization) noting that Baldwin threw down somewhere between 2.5 and 3 million gold-backed dollars evolving the Big Engine, spreading the wealth at some point by extending parts of the development to Alco and Lima (which is something I suspect, but can't prove, came to be used to help with the second Depression circa 1938).  

It might be noted that a more practical PRR train size was the 880 tons used in the T1 spec, also to 100mph but now with lightweight rods allowing practical 80" drivers for the high developable speed.  As you may know, PRR had a 'thing' for Atlantics as very-high-speed power (see the lightweight-train E8 Atlantic proposal at around the time of motor-train-competitive light consists a la Hiawatha) and running gear that was essentially a double Atlantic was right in the sweet spot to euchre, I mean entice PRR to spend what came to be an enormous sum on something that was very, very similar to what Yellott and BCR would pull from the late 40s to early 50s with the coal-burning turbine business.

In July 1936, PRR requested Baldwin Locomotive Works to submit a design for a 4-8-4 engine capable of handling a 2,000-ton train between Colehour and Harsimus Cove”

It should not be lost on you that that destination pair is freight-olny, at a time when PRR freight had a hard 50mph speed limit.  It would have nothing whatsoever to do -- at that time -- with passenger service.  The thing that is interesting is that, if given M1a-size drivers and the contemporary Timken rods, PRR would have had a locomotive that could be competitive with what became the N&W J, and with even slightly higher drivers produce the same kind of 'unanticipated' speed that the Niagara would demonstrate nearly a decade later.

“Two months after the conference, Baldwin Locomotive Works officials presented four designs to PRR: a 4-4-4-4 passenger locomotive that could haul 1,200 tons but exceeded existing weight and clearance restrictions; a 4-4-4-6 passenger locomotive that could haul 1,200 tons but also exceeded limits; ...

You will immediately notice that the latter is the ATSF engine design turned around to suit coal firing, and it would be interesting to see if the version pitched to PRR had similar 84" drivers.  I suspect the 4-4-4-4 was the infamous Baldwin design with 102-104' grate area and Baker gear with large piston valves, which PRR would subsequently 'improve' to get the weight down (and left us all suffering for many years as a result).
...a 4-8-4 freight locomotive with the same weight on drivers as an M1a, which failed to meet the requirements for a 2,000-ton train...
And of course what came out of this was the great horse-designed-by-a committee Q1 design, which was based on a 5/4 increase in M1a power net of a change to 77" drivers.  This always reminded me of the AMC project to make a 5/4 Berkshire (in what became the C&O T-1) ... which of course became the basis for the actual near-optimal PRR heavy freight locomotive in the form of the increased-driver-size Jia, but that's getting ahead of the story.

...an articulated 4-6-6-4 locomotive”

First, PRR had an announced and pronounced aversion to articulated power, and this was just at the time that practical fast simple articulateds were appearing (notably the N&W A class, which is almost the poster child for parent PRR's needs if they had wanted an articulated).  However, a moment's reflection will indicate that there would be problems with a four-wheel lead truck on a 4-6-6-4 with a deep firebox completely off the driver wheelbase, the sort of problems that led Alco to come up with the somewhat goofy Challenger type.  Baldwin was certainly not going to have the Alco design, and you can draw some conclusions about the size, weight, and other characteristics of a 4-6-6-4 instead of 2-6-6-4.

“PRR preferred 4-4-4-4 and asked Baldwin to consider a passenger version with 6 ft 8 in drivers and a freight version with 6 ft drivers” Interesting the array of duplex wheel arrangement configurations that were being discussed/designed behind the scenes already by this time.

Note that this is already pointed at a locomotive the size of Baldwin's proposed duplex, with 80" drivers, compliant with PRR's desired weight limits but with what was then ASSumed to be the over-the-top FA needed to make an unconjugated duplex anything but a slipfest.  The freight duplex of course is interesting because it was a 3/2 increase on the M1a (but with a hinge and extra complexity over a rigid-frame duplex) and that was more than prospective trains would be, especially in that age where there was a very real threat train length would be Federally limited to about 83 cars -- the thing that Ed King says sank the N&W Y7).

Particularly of interest for me would the designs that were rejected for being “too big”.

Not too big... too heavy, and it is critically important to appreciate the difference, as it led directly to the six-wheel trucks and enormous boiler size of the S-1 as built.

The only thing I have been able to find is descriptions of records of preliminary designs from the Lima Locomotive Works archives that are held at the California State Railroad Museum Library https://csrm.andornot.com/, in particular: 6-4-4-6 design dated Aug 11, 1937. Another 6-4-4-6 design dated Aug 17, 1937 A possible 4-4-4-4 or 4-4-4-6 design dated Feb 3, 1937

Of course these are related to the 'collaboration' between the builders that I referred to above; you're going to have to have them scanned and sent to you by CSRM or else get permissions to inspect the collection -- if you're not in a position to visit the West Coast easily, only the former is practical.  I'd post the request on RyPN as they'll give you the contact information to get that done at least cost.

Not related to the S1 but interestingly there is also a 2-6-6-6 preliminary design from as far back as Sep 10, 1929 and a 2-10-6 from Oct 24, 1925.

You need to be careful, because these are anything but duplex (or particularly modern) power.  We discussed the 2-6-6-6 a year or so ago either here or on the Trains forum (it was one of garya's "finds" in the railway trade press) and it was an upsized Erie Berkshire, for the Erie.  What it most certainly was NOT was a technical predecessor of the Allegheny type in most significant respects.  The 2-10-6 is one of Woodward's nutty aberrations: it is the colossal greatest of the drag freight engines, reliant on 'central machinery support' and main rods inside side rods to get the considerable augment reduced even at low speeds, a bit like an upsized A-1 Berkshire... and we all know the fun involved with those mid-to-late 1920s Berks with their articulated American Arch trailing trucks that didn't work in reverse.

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Posted by IA and eastern on Thursday, June 8, 2023 12:47 PM

What design of 4-8-4 were they looking at? Gary

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Posted by Overmod on Thursday, June 8, 2023 7:25 PM

IA and eastern
What design of 4-8-4 were they looking at?

My initial guess for a true 100mph engine in the 'necessary' window of time would be the select few 80"-drivered alternatives -- the ACL R-1 and ATSF 3765 class being two from them that ought to have qualified.  Note that this was not going to be an engine with 76" or 77" drivers; at that time PRR still considered the minimum for high speed to be 80", and while I suspect the stillborn E8 Atlantic would have had the 84" drivers, a rigid-frame 4-8-4 with the valve gear and rod design of that period would likely not.

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