PRR Duplexes and Experimental Engines ( S1, S2, T1, Q1, V1 etc.)

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Posted by Jones1945 on Monday, February 10, 2020 2:31 PM

Additional information about the PRR Q1 #6130 4-6-4-4 duplex as a dual service engine instead of a freight-only engine between April 1942 to June 1945:

  1. On April 10, 1942, H.W. Jones, Chief of Motive Power, told Altoona that the Q1, #6130, would be considered a passenger engine as far as striping and lettering were concerned. 
  2. On June 9, 1942, President Clement approved locating the keystone number plate above the center of the smokebox. He did not like it on the front cooler.
  3. In June 1945, during class repairs, the bronze bell was replaced with a steel one, since bronze was reserved for passenger engines.

Source: The Keystone Magazine Volume 39, Number 2, Page 30.

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Posted by Overmod on Tuesday, February 11, 2020 10:04 AM

Q1 was always a dual-service engine; few freight engines in the world, let alone one on a railroad with a hard 50mph peacetime freight speed limit, use 77" drivers.  

This even if we discount that wartime 'expediency' demanded nominal dual service capability to get something new like this past the WPB construction restrictions ... remember certain GS engines on Southern Pacific?

Note that the 'class repairs' date is a month after VE Day, at a time it was probably becoming very clear that there was little prewar advantage to the Q2s (a far more successful freight duplex capable of most PRR M&E freight speed if required).  Big order for T1s had been approved over 6 months ago.  

Who needed that thing as a passenger engine by that point?  It certainly wasn't reliable enough in a number of respects... (might be a touch of irony in there somewhere, as things turned out)

...and I strongly suspect the bronze bell may have gone to one of the T1s a-buildin'.  That would represent a substantial savings of cost, even in those days... 

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Posted by Jones1945 on Tuesday, February 11, 2020 5:15 PM

Overmod

Q1 was always a dual-service engine; few freight engines in the world, let alone one on a railroad with a hard 50mph peacetime freight speed limit, use 77" drivers.  

We know that Q1 was definitely a dual-service engine, but many railroad historians, authors, brass train manufacturers are under the impression that it was designed as a freight engine from day one. Before I updated Q1's wiki page, there wasn't a single word about 'dual service' or 'passenger train' in the context, but only the conventional belief about Q1 that the 77" driver was unfit for freight service. President Clement actually enquired the MP dept twice about the size of the driver on Q1, it wasn't a reckless decision. 

 

"Coal-Burning Steam Freight Locomotive"

 

Regarding the performance, Neil Burnell, the author of the Keystone article said that he has previously suggested that the Q1 might have been successful as a passenger locomotive, hauling the heaviest consist, and he believes this is consistent with its power output of 4800dbhp, equivalent to the corrected dphp of T1 #5539, when tested on the C&O. His conclusion is backed up by Q1's revenue run records from May 1942 to July 1942, which is included in the Keystone Magazine. When Q1 was hauling 5000+ tons freight trains, its rear-engine always slipped when starting, which sometimes led to stalling with sandbox empty!                                                                                        

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Posted by Overmod on Tuesday, February 11, 2020 6:38 PM

I don't remember the source, but the Q1 wound up being an incremental increase in power over the M1a Mountain, but they increased the diameter speed at the same time they took down the dynamic augment, not something you do unless you have a very good idea you'll be running heavy trains at far over PRR freight speed.  I think they thought of it as being an incremental step past a double-Atlantic for highest speeds: a piece of motive power that would do the work of doubleheaded K4s on everything but hell-fast trains.  And that, it would have done.

It needed to be conjugated for serious freight work, just as the S1 would have had to be.  And it needed precisely the emphasis on long TOFC consists or extended M&E at elevated speed that constituted a hole in the late-Forties operation -- no more long, high-speed freights as in wartime; no reason to accelerate conventional track-pounding interchange freight past 50mph...

... and of course when the time came, F units on the one hand and surplus E units on the other hand filled any gaps the Q1 would have excelled at.

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Posted by Jones1945 on Thursday, February 13, 2020 8:24 AM

Overmod

...I don't remember the source, but the Q1 wound up being an incremental increase in power over the M1a Mountain, but they increased the diameter speed at the same time they took down the dynamic augment...

Yes, the Q1 was in part due to President Martin Clement's request for a feasibility study as to the possibility of expanding the TE of the M1 by mere 10000lbs. After a thorough study by the Mechanical department, they replied that although some improvement in TE could be obtained, it wasn't an economical option since it would reduce the efficiency of the M1's boiler. A trailing truck booster could be applied to increase the engine's ability to start a heavier train, but this would be an expensive appliance only suited to use at low speed. They thought it was impractical to upgrade the M1s. Lima offered a proposal to rebuild one M1 into a 4-8-4 with poppet valves equipped, but PRR rejected. That would have provided much of the additional power Clement desired.

Neil Burnell, the author of Keystone Magazine's Q1 article, stated that he read official files of Q1, but he didn't have access to the actual design information. I believe the engine was build as a competitor to Baldwin's T1 4-4-4-4, given that the project was executed and carefully monitored by Clement himself, with Raymond Loewy involved for the streamlining. Note that the design work of Q1 started as early as 1939. It seems that Pennsy wanted to build something a bit smaller than S1 and much more practical, a dual-purpose engine that could have handled both fast freight service and passenger train service, all by Pennsy themself.

Neil Burnell also stated that most of the PRR Test Department files were destroyed by an NYC official in the PC era, we probably never know if Q1 ever hauled passenger train for testing, why and who stopped the engine from becoming a passenger train engine, also could have been seen as Baldwin's duplex competitor between 1943 to 1945. Did Baldwin negotiate with PRR, persuaded them to use their patented duplex design, the T1 prototype in 1942 exclusively for PRR's passenger trains, instead of PRR's duplex design, the Q1? We will probably never know.

One last thing, Clement suggested equipping Frankin poppet valve gear on Q1's rear-engine but was rejected due to inaccessibility for maintenance of the cambox. Ironically, the poppet valve gear cambox on the T1's rear-engine was also inaccessible for maintenance!

 

 

Overmod

It needed to be conjugated for serious freight work, just as the S1 would have had to be.  And it needed precisely the emphasis on long TOFC consists or extended M&E at elevated speed that constituted a hole in the late-Forties operation -- no more long, high-speed freights as in wartime; no reason to accelerate conventional track-pounding interchange freight past 50mph...

Just as those Southern Pacific GS-3, GS-4, and ATSF's Northern with 80" drivers. They were assigned to haul freight trains in the late 1940s. TE of PRR T1 was 64,653lbf, much higher than the L1s 61,465lbf, but they didn't have the chance since there were already 574 L1s, let alone the I1s/I1sa were much more powerful in terms of TE...

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Posted by Overmod on Thursday, February 13, 2020 1:03 PM

Be careful here because "TE" and power are not at all the same thing.  What you want to examine is not 'starting tractive effort' but the development of that additional 5 tons of tractive effort at some particular speed.

This is well-remarked in discussions of the early Berkshires, whose TE might be only indifferently higher than a predecessor Mikado (for a sizable increase not only in overall engine weight but in non-adhesive weight) but whose over-the-road performance with tonnage might be definitively better, and faster.

Part of the issue with PRR not doing a 4-8-4 is that, of course, the Q1 is a locomotive with 5/4 the adhesion of a Northern, with the same front and rear steering characteristics and at least equivalent firebox capacity, but with far less augment than any contemporary one.  Another part of the issue is that for high-speed passenger work PRR was off in a different duplex direction, but one that was not viewed as 'overlapping' what the Q1 represented.

(Note that the two Baldwin T1 'adaptations' of the double-Atlantic passenger duplex were ordered in late June of 1940, well in advance of the October 9th 'greenlighting' of the Q1 for production ... this is not just an example of 'ours' vs. 'theirs' production.  In this light the option for 'common' Franklin type A gear for the rear engine may make a little better sense, and the difficulties with packaging the cambox not yet as obvious as they would become. 

Perhaps the most interesting detail involves the Q2s, which were far over the horsepower the Q1 could ever develop, and which included boosters as part of their design.  I find I can't locate a copy of the TE-at-speed graph I found for the V1 turbine (which is, in color, at the Hagley Museum in Delaware) but I've posted it in at least a couple of threads and someone may be patient enough to locate and repost it here.  It is interesting to consider what the TE recorded for that locomotive (there is a very distinct 'kink' in the plot where the booster cuts out) represents ... or what corresponding figures for the Q1, which essentially would have become the near-equivalent of a 77"-drivered Challenger at starting, would have been...

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Posted by Jones1945 on Saturday, February 15, 2020 4:26 AM

Overmod

Be careful here because "TE" and power are not at all the same thing.  What you want to examine is not 'starting tractive effort' but the development of that additional 5 tons of tractive effort at some particular speed.

This is well-remarked in discussions of the early Berkshires, whose TE might be only indifferently higher than a predecessor Mikado (for a sizable increase not only in overall engine weight but in non-adhesive weight) but whose over-the-road performance with tonnage might be definitively better, and faster.

Part of the issue with PRR not doing a 4-8-4 is that, of course, the Q1 is a locomotive with 5/4 the adhesion of a Northern, with the same front and rear steering characteristics and at least equivalent firebox capacity, but with far less augment than any contemporary one.  Another part of the issue is that for high-speed passenger work PRR was off in a different duplex direction, but one that was not viewed as 'overlapping' what the Q1 represented.

(Note that the two Baldwin T1 'adaptations' of the double-Atlantic passenger duplex were ordered in late June of 1940, well in advance of the October 9th 'greenlighting' of the Q1 for production ... this is not just an example of 'ours' vs. 'theirs' production.  In this light the option for 'common' Franklin type A gear for the rear engine may make a little better sense, and the difficulties with packaging the cambox not yet as obvious as they would become. 

Perhaps the most interesting detail involves the Q2s, which were far over the horsepower the Q1 could ever develop, and which included boosters as part of their design.  I find I can't locate a copy of the TE-at-speed graph I found for the V1 turbine (which is, in color, at the Hagley Museum in Delaware) but I've posted it in at least a couple of threads and someone may be patient enough to locate and repost it here.  It is interesting to consider what the TE recorded for that locomotive (there is a very distinct 'kink' in the plot where the booster cuts out) represents ... or what corresponding figures for the Q1, which essentially would have become the near-equivalent of a 77"-drivered Challenger at starting, would have been...

Speaking of that "distinct 'kink' in the plot" where the booster cuts out, here is a graph and data from Keystone you might find interesting:

 

 

It would be even more interesting if T1 and Q2's data is included, and a graph that can compare the change of dynamic argument of a duplex and "nonduplex" (including doubleheaded K4s). 

Pennsy insisted to develop their own dual service duplex engine instead of asking Baldwin to design and build one for them in 1940 after they placed the order of two prototypes from Baldwin just a few months ahead. One interesting fact many missed was that Pennsy did require Baldwin to design a 4-4-6-4 frigid frame duplex as early as 1936! 

Pennsy was so determined to Ralph P. Johnson's idea, the T1 prototypes #6110 and #6111 cost $600,000 while the Q1 alone cost $595,000, all three of them cost $1,195,000 (= $22,019,667.50 today) in total. I wonder how much did an EMD E6 A-B-A set cost in 1940... I only have Paul W. Kiefer's 1946 steam-versus-diesel trial figures, which show the "Approximate relative first costs" of EMD E7 A-B-A set was 214% of a single NYC Niagara, but the overall maintenance and operation cost of a Niagara was very competitive. E8 came and put a full stop to almost everything...

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Posted by Overmod on Saturday, February 15, 2020 8:48 PM

I believe Q2 IS listed; it's the 'fifth' line on the chart, the top one.  

This chart is also proof that the Q1 was built with a booster: the notched trace proves it.  This is where the steam overflow going into the booster at high speed is redirected to the main cylinders once they are operating at a cyclic rate sufficient to make 'better use' of what was being directed to the small, full-cutoff engine operating at excessive speed.

Whether a Q2 could effectively exert the near-starting TE corresponding to that trace under 'real-world' PRR conditions is another thing!  But there is no question why PRR didn't think it needed a 'bigger' articulated design...

Note the ghastly fall-off in TE at speed once the Q1's booster cuts out.  They badly needed better steam-circuit design and valves ... to start with.)

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