I know from various sources that the T1s were very dirty, i.e. the smoke or soot from the stack tended to cover the engine and cab in slime and filth, and they also had a bad habit of slipping the drivers at high speed.

Why would the T1s be dirtier than any other engine? Hard to believe it had combustion processes that were any less efficient. Is there definitive knowledge of the cause of the high speed slip problem, and possible solutions?

PRR T1 Article
hkading@rypn.org

> I know from various sources that the T1s
> were very dirty, i.e. the smoke or soot from
> the stack tended to cover the engine and cab
> in slime and filth, and they also had a bad
> habit of slipping the drivers at high speed.

> Why would the T1s be dirtier than any other
> engine? Hard to believe it had combustion
> processes that were any less efficient. Is
> there definitive knowledge of the cause of
> the high speed slip problem, and possible
> solutions?

Lord knows I'm no T-1 expert, but my limited understanding is that the sooting problem was not more or less efficient combustion, but rather aerodynamics--it wasn't a question of what came out of the stack, but rather that what came out of the stack tended to get laid down on the engine itself. This impression may have been compounded by the fact that the PRR's general washing and cleaning practices were starting to get a little more lax by the T-1 years.

As for the second, I always thought the sliperiness was just an artifact of the extremely high available horsepower applied, via four cylinders, to two sets of two-coupled axles--jog the throttle, and the avaialble horsepower would threaten to overcome the available adhesion.

However as I say I'm on thin ice so I await correction by the T-1 gurus.



eledbetter@mail.rypn.org

Most of the references to dirt on the T1 is from coal dust blowing in through the back of the cab from the tender. As far as smoke is concerned, the somewhat smallish grate area may have contributed to this condition because of higher firing rates to achieve the required evaporation. As a guess, the poppet valves could have contributed to this condition because the T1 could be operated at very short cutoff (less than the traditional minimum of about 30%). This would cause the smoke to lay back over the top of the boiler instead of lifting.

The much-discussed slipping problem was mostly directed toward the two prototypes. From what I've read, the 50 production units were easier to handle and the 5 or 6 that had their cylinders reduced to 18-3/4" didn't cause any particular problems either. I have copies of several memos written when the T1's were tested on the C&O and N&W, and in both cases, the correspondence specifically stated that the engines were not slippery.

The best source of first-hand commentary I've found is Vernon L. Smith's book, One Man's Locomotives. He lists several recommendations for improvement, and comments favorably on the design as a whole. Several articles written by the late Charlie Meyer for the Friends of the Pennsylvania Railroad Museum (located in Strasburg) went into considerable detail with respect to the good and bad points of the locomotives, and how the PRR worked to resolve their operating difficulties. There is a lot of research still going on about the T1 and more information will likely be forthcoming.

As you probably know, the T1 has been the subject of much myth and editorializing over the years, and it's always amazed me how its problems seemed to grow with each new story back in the 1960s. Only recently has any new research been done, nd some of the myths are being debunked. From what I've read recently, many of its problems were resolved from 1946-1948, but the economics of the diesel was one thing that no steam locomotive could overcome, regrettably.

stephensond@stb.dot.gov

Only recently has any new
> research been done, nd some of the myths are
> being debunked.

And happy I am to have my myths corrected, thanks!

eledbetter@mail.rypn.org

I might point out that, from a technical standpoint, the PRR T1's were hardly the success everyone in PRR-worship land claims them to have been. It's amazing the terrible engineering that can be successfully hidden by "handsome" styling and looks.

The best "independent" analysis of the PRR T1's and other duplex designs about that I have seen is Loco Profiles' "Loco Profile 14: Pennsylvania Duplexi", reprinted as a chapter in "Locomotives in Profile", vol. one or two, which were written ca. 1970 from the British and European engineering standpoint. If I recall correctly, the T1 section concluded with the scrapping of the last T1 and "So ended the greatest fiasco of American steam locomotive design in the twentieth century." A bit of an exaggeration, to be sure--consider the UP's steam-turbine-electric and other turbine projects (and I am NOT opening the floor to "worst American steam" debate, thank you), but the British analysts I have spoken with are mystified as to why the PRR stuck with the T1's as long as they did.

LNER4472@gateway.net

>British analysts I have
> spoken with are mystified as to why the PRR
> stuck with the T1's as long as they did.

Of course, these are the same analysts that abandoned the Duke of Gloucester when only minor fixes were needed to produce a locomotive which didn't have the problems it originally exhibited. By the way, one book I remember reading said that the problems with the T1s may have been fixed by applying standard valve gear, such as Baker. Any comments on this?

wilkidm@hera.wku.edu

One was equipped with Walschaerts valve gear and reclassified T1a. Never read if it was comparatively tested or not. Another was equipped with Franklin Type B rotary cam poppets with outside drive instead of the inaccessible inside drive of the Type A. This was a considerable improvement particularly from a maintenance standpoint.

stephensond@stb.dot.gov

I should have added a very recent book, written by a British author, Philip Atkins, who is associated with the Railway Museum in York. The title is Dropping the Fire, a review of the last of steam worldwide. He wrote a very even-handed review/comparison of the PRR T1 and NYC Niagara that occupies an entire chapter of this book. It presents an interesting contrast to Brian Reed's chapter on the PRR Duplexii in his Locomotive Profiles series. I highly recommend it.

stephensond@stb.dot.gov

> I should have added a very recent book,
> written by a British author, Philip Atkins,
> who is associated with the Railway Museum in
> York. The title is Dropping the Fire, a
> review of the last of steam worldwide.

Dave,

Any suggestions on how to get this book? I checked on ABE and couldn't find a listing. Do I need to travel to York?

Thanks

a231pacific@aol.com

The book is available direct from the publisher:

Irwell Press
59A, High Street, Clophill
Bedfordshire, MK45 4BE
UK
or e-mail at

chrisirwell@aol.com

When I bought the book in March of this year the price was 14.95 (british pounds, can't find the symbol) plus 7.50 air mail postage.

stephensond@stb.dot.gov