Steam & Excursion > Big Boy Question

Hello all,

In older photos of UP 4-8-8-4s from the 1940s or so, one can see an assortment of pipes on either side of the locomotive's headlight. Later photos from the late '50s near the end of their lives do not show these pipes, and none of the preserved examples seem to still have them. Does anyone know what purpose they served and why they were removed? Thanks in advance.

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Weren't they to cool just-compressed air?
And they got moved to some other spot
on the engine?

That's pretty much what's behind the nose doors on the engine.

Out

The compressor aftercoolers mounted behind the headlight in the build/early photos were relocated because the pipes would crack due to vibrations in the original location. I believe they were relocated to behind the compressor shield.

Kratville's book explains that the first order came with the fin type after-coolers on the pilot deck, just below the handrails. This was 4000 - 4019. The second order had these pipes placed behind the pump shield. That was 4020 - 4024. Both types of after-coolers had issues with condensation and ice. Consequently the pipes on the pilot deck were replaced over time and placed behind the shield, but apparently there were still issues with this arrangement.

With revived interest in the Big Boy, wonder if the Big Boy book will get a re-print? Or is it still out there as new?

Also referred to as radiation piping. Air from the pumps is both hot and moisture laden. These were to cool the air and condense the moisture out. Same purpose as the long runs of pipe beneath the running boards on many locomotives.

In the original location they were subject to vibration and also to damage when the smokebox door was opened, which was necessary at the end of each trip to inspect the front-end netting and the superheaters and repair as necessary.

The fins would get bent up and the vibration caused the pipes to crack from work-hardening.

Moving the coolers behind the air pump shield (like the 3900s were from the factory) solved all of that, as the mounting location was not subject to either of the above afflictions.

IMO, the book needs a good proofreader and some serious editing as to organization and some updates. It's a good read as-is, but jumps all over the place, even contradicting itself occasionally.

Here is a UP photo of 4002 with the cooler piping "out front."

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Realist Wrote:
-------------------------------------------------------
>
> IMO, the book needs a good proofreader and some
> serious editing as to organization and some
> updates. It's a good read as-is, but jumps all
> over the place, even contradicting itself
> occasionally.


Agree with this statement!

Scott Griggs
Louisville, KY

sgriggs Wrote:
-------------------------------------------------------
> Realist Wrote:
> --------------------------------------------------
> -----
> >
> > IMO, the book needs a good proofreader and some
> > serious editing as to organization and some
> > updates. It's a good read as-is, but jumps all
> > over the place, even contradicting itself
> > occasionally.
>
>
> Agree with this statement!
>
> Scott Griggs
> Louisville, KY

I agree that Kratville's excellent book really
desperately needs some really GOOD editing. In
come parts, it is impossible to tell even which
YEAR things happened! And it does jump around
a lot. And the part about the 4005's conversion
to burning oil is woefully incomplete, because,
even though the book was published in 1967, well
after the UP had stopped using steam locomotives,
Kratville dos not tell the rest of the story about
the 4005 -- that the UP worked on the 4005 and was
able to get the locomotive to work quite well using
oil. I just can't help but wonder what else he
left out.

Other than that, it is an excellent book.

His books seem to get better as they get newer. While I'll admit to not yet really reading in depth his 9000 Class books, they are a great improvement over his earlier books. (Added index, very in depth breakdown of parts, modifications and testing among other things.)

up3985 Wrote:
-------------------------------------------------------
> His books seem to get better as they get newer.
> While I'll admit to not yet really reading in
> depth his 9000 Class books, they are a great
> improvement over his earlier books. (Added index,
> very in depth breakdown of parts, modifications
> and testing among other things.)


I just bought the Kratville UP 9000 book volume 1 and am waiting to receive it. I look forward to reading it and will look for the improvements. That book costs a pretty penny in the secondary market!

Thanks for that photo of 4002. I liberated the stencils in the Train indicator while it awaited scrapping in the Geneva, UT steel yard, for which my dad made a wooden mockup of the box, donated to San Mateo County Mudeum when I left town for PG a couple months ago.

Steve Donaldson
Pacific Grove, CA



Edited 1 time(s). Last edit at 12/15/17 20:52 by SteveD.