Hi Dave
Well , the J isn't that long - I mean the ‘North Folk's and Western’ J – more of a body-builder locomotive. Actually , the PRR T-1 isn't all that long , if you come to think that half the length is just high capacity tender of approx same mass , loaded , as engine and of same number of axles –
and that brings us to your remark >> an improvement? <<
I could have included technical improvements , but I confined depicted changes to appearance , since entering into the field of technical changes – although confining considerations strictly to technology known to steam loco design in 1945 , to be sure ! – would have considerably intensified the overall changes applied and it would have mixed two sides that I believe should go together in a good design , however I wanted to keep apart for this discussion – except for one point , which was to trim down tender loaded mass to allow for using 2 x 6 wheel bogies to relieve engine from 1/4 of former tender dead mass to pull at speed .
As it was , the T-1 was an example of the price paid in performance loss for low overall thermal efficiency , composed of low combustion efficiency , worsened by low thermo-dynamic cylinder efficiency and low draughting efficiency (since the lower the latter two , the higher steaming demand and even higher coal consumption super-increasing mainly because of degrading combustion efficiency , increasing unburnt losses – by the way this again caused further costs through higher maintenance costs since higher thermal stresses on boilers lead to super-increased amount of work necessary on staybolts replacements , tubes and firebox tube plate foundation ring and other critical parts of the Stephensonian concept boiler) . Especially , fast running passenger engine suffered severely from excessive tender mass necessary to compensate high consumption rates with low thermal efficiency , since tractive effort at speed was not high for a given output - not even at 6500 ihp . Because the rolling resistance grew with speed , both factors of the power equation - speed and traction effort - grew at the same time with heavier tenders and with higher speeds and that meant a radical increase of power lost from cylinders to traction bar at higher speeds .
That is why with freight trains of 12000 tons , like the ones taken by the J-1 and Q-2 class on the Sandusky line , sixteen wheel tenders didn't matter much and locos could even take auxiliaries water tenders if that avoided water stops – not so in passenger traffic . The Pennsy had learned that when they tried twelve wheel tenders on some K-4s but obviously had believed the problem would ease with stronger engines that just had the power to pull heavy tender plus heavy train . While that was true , the fact seems to have gotten somewhat blurred , such engines consumed again more water and coal and thus tended to resolve the problem but incompletely – if on a generally higher level of traction work . True , the Pennsy made an effort at improved cylinder efficiency with Franklin poppet valves – however , without due adjacent improvements there wasn’t much to be gained . Strengthening but one link in a weak chain can never supply a full answer to a problem – a simple fact , yet all to often ignored in efforts to improve the steam locomotive’s efficiency .
Where such single-focussed attempts met with wide spread attitude to existing technology like “It might help , but we can’t use it ‘cause it’s foreign” results of trials had to be disappointing and all to often caused resignation to keep bearing down the same hammer on the anvil until the hammer wore out – which pretty much was the case for US steam in 1945 – 49 .
This is generally agreed as ‘the critical four years post-war period’ , although , as my late father had told me , memorizing professional life in steam loco construction during this period , the diesel’s full implementations introducing imminent and far reaching changes to railroad and locomotive business only became evident in hindsight while during the actual time being many of those working with or for steam had continued for years largely missing to perceive the ‘writing on the wall’ or (to quote my father’s saying) “The New Day Dawning” with the diesels ante portas ; or they didn’t realize full momentum of the situation , firmly believing “steam can never be replaced as a mainstay of railroad traction” and would some way somehow just survive the diesel onslaught . if in future parting traction with the new power .
One misconception popular during the initial years , he said , was to belief the diesels would only take over passenger service ; later it was still believed diesels would be too expensive for every-day low fare bulk freight traffic .
It is only by difficulty of getting a clear overall view on implementations of radical changes when living in the very time when they actually happen , it can be understood how in search for an answer to steam’s ‘life-threatening’ question of the time , as late as 1949 Lima could come up with offering extensions of arguably marginal importance to existing design path such as a double Belpaire firebox , enlarged over six trailing truck wheels in an eight coupled power configuration with a 4-10-2 super tender , i e yet more carrying axles with still the same number of driven axles as in a dual purpose medium driver dia 4-8-4 – enlarging yet again on what such power as the Greenbriar , N&W J , you name them , already had in abundance – i e steam – while not adding a pound to what was desperately needed : starting tractive effort which really was steam's Achilles' heel . The Lima4-8-6 offered a great (superb?) machine in categories of steam’s Super Power – only , those categories had become obsolete , the proposal did not answer actual demands . It was a classic case of engineering having failed to ask the right question and thus having formidably missed the mark .
Not before the last efforts of what was then put high hopes on as ‘modernization of steam’ – in hindsight rather isolated re-animation attempts of steam in coma – had faltered until 1953 did the last of unwavering steam promoters among engineers concede the battle was lost .
Since then , there have been many more examples of blindness of professionals in various industries or economy to big changes coming up “because things will never change from what they are since that’s the way it has always been” , see IBM , see Lehman Bros , see General Motors , see examples enough in ‘Old Europe’ too .
Regards
Juniatha
S-2 with Witte smoke deflectors as put on by Pennsy .
By size and shape these could really have been spares
obtained from a 52 class light Decapod , or almost ;
however they can hardly have worked that way ,
mounted ‘directly’ to the smokebox sides .
6200 on diet after my quick chirurgical job of
running board straightening and tender bottom lifting
(weight watchers anonymous)
and yes I lifted some smoke , too .
