Steam & Excursion > Western Pacific 4-8-4

WP # 481 at Oroville, Calif., August, 1948. Photo by the late Guy Dunscomb.

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Another Dunscomb beaut...look at the light on the side of the engine!

Tom

Beautiful image! It does kinda make you glad though that SP didn't apply smoke deflectors to their GS6s!

HUSKERHERB Wrote:
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> Beautiful image! It does kinda make you glad
> though that SP didn't apply smoke deflectors to
> their GS6s!

They probably would have looked better if placed in the more common location on the outside edges of the running boards.

Africansteam

Right you are Africansteam. The WP look was a little asymmetric!

A glorious photo, thanks for posting SierraRail.

I'd much enjoy knowing the real story behind the placement of those lifters. Personally, I believe it's a concession to a combination of visibility and access as I can't imagine they're more effective in that location than they'd be outboard. I wonder if any tests were made prior to determination of final location?

John

I have absolutely no historical or technical knowledge on which to base this, but in thinking about this I have wondered if the placement could have been dictated by the times. As these locomotives were built and delivered during the war, could it not be possible it was a night visibility issue. As most know, the railroads were required to use hoods and other devices to limit the light from all sources on the locomotives. Given the curvature of the WP and the limited amount of light, possibly they were inset like that to give the crew maximum visibility with limited light. In fact, I wonder if the same reason does not account for the use of the deflectors in the first place.

When were the deflectors installed?

On #481, the deflectors were installed in April, 1947. The first ones were installed on # 485, in Sept., 1946. Last one was # 483, in Jan., 1948.

Well, that shoots my wartime blackout light theory all to hell :)

I knew you were WAAAY off base on that one, drew! Naaaaaah, just kidding. By the way, perhaps the students of WWII, especially the Japanese side of things, can answer this one: Were the fears of sub attacks, night bombing and other possible war-related problems largely abated on the west coast by the time these engines were constructed? I rather think they were on the east coast, the U-boat problem having largely been dealt with. So, if this is true, I'm guessing the early "black-out phobia" might have cut back a few notches by the time these engines were built. I may very well be totally off base.

Given that it's extremely unlikely any differences existed in the skyline casings between the SP and WP engines (since, if I'm recalling correctly, the WP engines were simply diverted from the WPB authorized SP order, weren't they?), and we don't know of any efforts by SP to utilize any extraneous devices for smoke management outside their casing design, it seems likely WP found their operating realities resulting in undesirable visibility and perhaps other problems. These would most likely have shown themselves present during the expected drifting periods, and possibly even in small throttle opening situations.

I suppose the lifters were considered a relatively quick fix, given their success in other parts of the world. It's interesting to read of the spread of time in fitting the engines, especially given the small number of locos in the class. Note, too, that this program was undertaken at very nearly exactly the same time Union Pacific was dealing with problems encountered with the final class of 800's.

I don't mean to "steal" this thread into another rather unrelated topic, however regarding the 800's, the initial lifter experimentation was conducted while the FEF-3's burned coal, as constructed. One might well expect the smoke situation to have been reduced somewhat by the change to oil firing given the fireman's assumed ability to curtail smoke more rapidly than may be accomplished with coal (thinking specifically about the problems during drifting). However, it's a fact that UP continued this program and quite a number of engines were not fitted with lifters until well into 1950 and later, and all had been converted to oil not less than four years prior. Those who could answer this "question" with specifics are unfortunately deceased, though I do personally hope for a chance to study this matter at some point, because it's my guess that these engines (and possibly the 3700's) displayed a need for a slower adjustment from "big fire" to a lower level of firing which resulted in their smoke problem, possibly related to firebox volume. Certainly, the myriad other oil-burning UP power which did not receive lifters were using the same fuel, so that can't be an element. More, it's not down merely to speed as the problems with the 800's existed at both low and higher speeds.

Anyway, sorry to get off on that tack, just wanted to mention it as it's always been interesting to me.

I recall the comment of Walter Thrall, U.P. engineman and photog, who remarked about the lifters on the 800's as follows: "They didn't help the smoke problem when drifting. All they did was ruin my shots of a good lookin', space coverin' engine!" Amen. I don't believe there was any "eared" loco that looked the better for it.

The latest Railfan and RR mag has an article about CP 2816, and states that smoke lifters were tried on her in two configurations, inboard on the running boards a la WP, and outboard on the boards as most others. Neither were effective at low speeds. The many different approaches to "lifting" smoke have always fascinated me. I have a photo of UP 815 sporting an SP/WP skyline casing. I guess the roads experimented with a lot of different concepts.

When I think about this smoke subject, I have read or heard very little about this type of problem on SP steam power, but the WP seemed to have this trouble on both the 481 class Northerns & the 171 class ex-FEC light Mountains.
One small thing, although the WP & SP engines were considered pretty much the same, the WP machines equalization put more weight on the drivers, thus increasing the factor of adhesion. SP did the same to one of their GS-6 types that was assigned to the San Joaquin Division & ran over the Tehachapis...it might have been 4463.

Tom

The UP Challengers with ears looked great!

The pinnacle of locos with 'ears' was NYC RR's 
4-8-4 Niagaras .   

As with the Daylight locos, you want to have a smooth boiler top,
to limit low-pressure areas from trapping your smoke.

When the engines are running on flat-land, the throttle is being used to 
reduce steam flow to the cylinders, and only partly open; so, the smoke-trail
barely clears the top of the boiler.  The steam has plenty of energy to 
use effectively at the pistons, by virtue of its very high amount of super-heat.
"Superheat" is the steam from the boiler which is re-routed through steam
piping back into the path of hot, burning gasses from the firebox.  

Steam, when boiled over the firebox is steam at the same temperature 
as the water that boiled it.  No matter how hot the fire, you can't 
get hotter steam, with a hotter fire!  It's called 'heat-saturated' steam.

BUT... if you re-direct the saturated steam through a system of pipes 
in the path of the flames and hot gasses ( 3,000F, at carbon's highest 
flame temps), you can increase the molecular vibratory amplitude,
'increased steam temperatures', the heat-saturated steam can be 'superheated',
to higher temps; but, limited by the 'flash temperatures' of the tallow-based
cylinder lubricating oils.  So, 700 degrees is the hottest steam that can work
in piston-driven locomotives.  Typically, modern steam boilers generate 
saturated steam at nearly 400 F, which gets "superheated"  up to
a total temperature of 700F.

So, with the Niagara's the intended air flow is to have the "crowded air" curved over 
the boiler top, and behind the smoke stack --- in a way that lifts the smoke
trail well-clear of the boiler-top.  The 'ears increase the velocity of the air-flow
over the boiler-top.  It's a dynamic air-flow device, it only works when at high-speeds.

The air gets crowded by the space between the 'ears being suddenly reduced
by the rushing smokebox front...the resultant crowding increases the velocity
of the whirling air, aft of the smoke stack, and lifting the smoke trail clear of
the boiler-top.

​W.
 



Edited 2 time(s). Last edit at 04/22/24 19:26 by wcamp1472.