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Steam & Excursion > Camelbacks

Date: 01/16/23 18:47
Author: ApproachCircuit

Looking at various Camelbacks doesn't make much sense to me.
Why were camelbacks designed the way they were??
Any advantages?


Date: 01/16/23 18:51
Re: Camelbacks
Author: swaool

Maybe this will help:

mike woodruff

Date: 01/17/23 06:32
Re: Camelbacks
Author: wcamp1472

The Wikipedia write up is good.
Read it, first.

However, there's more at work here.
Anthracite as a fuel was used in homes and buildings because 
it burned without dark clouds of carbon dust (visible 'smoke') bekching into
the air.

However, it generated immense CO2 pollution in metropolitan areas, and
the air over cities was brown with both automotive exhausts ( high quantities 
on leaded motor fuel, fine particle coal smoke and additional pollutants, leaf-burning,
etc. so, afterWW2, in cities political pressure pressure grew to stop burning coal
in homes and buildings.

But, at the end of the 1800s, Anthracite was THE fuel used for homes and
businesses formerly using wood fuel for both rail and buildings was
being phased-out.  

Anthracite for heating purposes  was sold in various sizes with different names
relating to lump sizes.  At the mines, sloping moving belts were lined with children,
on either side, to pick & sort out the varoius, commercially marketable lump sizes.  
At the very end of the line, was the unsell-able fine coal dust: 'culm'.
 About 20% of the coal on the belts was that dust-like carbon fuel.  
Great mountains of culm soon we're growing around the mines where coal was sorted.
Still extant, today, all over north eastern Pennsylvania.

Back in the day, if railroads could figure out how to burn culm, they could have
"free" locomotive fuel.

Anthracite burns slowly with low, blue flames, and some redness.  Flames do
not spread laterally; so, to have a fully-involved grate, new fuel must be added
on top of an already burning firebed.   It burns slowly. which means most of its
heat is radiant-heat, ( absorbed by the large, curved crown sheet --- stretching
over the whole grate area) not much is conducted heat, but the hot gasses carry
convected heat into the boiler tubes ---where the water quickly cools-down to the
residual heat of the convected gasses.

From writer Adam Burns,( internet source):  
"The Wootten Firebox was an interesting creation that was patented by John E. Wootten
in the 1870s to burn low-grade anthracite coal.  Its development came about from a
practical standpoint as a means of finding a use for leftover slag that was being tossed away. 

The massive size of the firebox resulted in a fascinating and unique locomotive design
known as the Mother Hubbard or Camelback, which resulted in the cab being placed
atop the boiler."

Early experimenters, tried many ways to burn the stuff, but it was not
easy to have to build 'test' fireboxes just to learn what did NOT work.

 Wooten finally struck the successful combination of an extremely wide grate area
( for it's time), compared to smaller grates that had burned wood and
the soft coals).  Typical grate areas for modest size engins like 4-6-0s & 2-8-0s
were fired by Anthracite grates of 100 sq ft.  Typically, they were as wide as you
could get, about 10- feet wide.  And, many used two sets of Butterfly firedoors...
in order for the fireman the reach and fill the rear corners...

So, crews learned to prepare an Anthracite fire thick and wide,  The fuel burned
slowly, so hand-firing was possible, with extended periods where firemen could
temporarily rest.  It was also dark in there, too---- compared to the bright fires of 
soft coals.  Additionally, Anthracite left a large amount of ashes, for the heat generated.

But, two economic factors were being developed that would demand larger
and larger locos: First: the application of easily controlled, universally-equipped
air brakes for trains ( every freight and passenger car had to be equipped
with standard airbrakes, or the system wouldn't work --- for such a 'hybrid train).  
Factor 2 was the development of a successful superheater design:
the 'Schmidt' superheater.

With the growth of 'universally accepted" airbrakes allowing very long trains
to be moved, the old, saturated engines soon required two or more firemen
to keep the soft-coal firebeds supplied with fresh fuel at a fast enough rate
to keep-up.

 'Saturated' term means that the steam produced by the boiling water is the
same temperature as that boiling water.   Adding more heat to the water
does NOT raise its temperature, but it boils more quickly.  The steam is said
to be "heat-saturated", which fits the definition of being the gaseous-state of water:
'steam'.... as long as the pressure remain unchanged.

However, as the steam flow moves towards the lower pressure of the cylinders,
it's temperature necessarily drops, and a portion of that flow condenses-out into
fine water droplets, we mistakenly call 'steam'.  The very same tiny 
water droplets we see in the sky's dramatic clouds --- but we don't call clouds 'steam'.

So, superheating allows the steam flowing to the pistons to slightly cool down,
without condensing into water droplets..... it still is in the 100% gaseous state.

So, you can add temperture to the steam flow.   Like, you could have 'saturated'
steam at 350F, and using piping in the flame path, add another 300F of temperature
yeilding a 'superhested' steam temperature of 650F headed to the pistons.... you
wouldn't get down to the water droplets-stage, until you had expanded the volume
and brought the pressure down to below the original 350 degrees.

So, by about 1915, builders were rapidly delivering superheated locos,
that could haul long trains, with all the cars equipped with easily-applied
and released air brakes.  In case of train separations, both sections of the
rolling train could safely be brought to a smooth stop.

Anthracite-fueled locos soon became technologically obsolete---
trains became  too heavy and too long so that the grates burning anthracite
couldn't keep-up.

The clearest example is how, in the mid 1940s, Reading Company took
the Wooten firebox of 2-8-0s and married them to boilers large enough to
successfully power 4-8-4s.

Such locos are examples: 2100 & 2102, both carrying their original Wooten
( Anthracite) fireboxes, but producing near 5,000 db hp, with their superheaters,
stokers, big pistons and 70" drivers..... all while burning Bituminous coal.

So, that's the story of 'why' the early variants had the cabs for the engineer
moved ahead of the very wide fireboxes of the Camelbacks.

Evolution in technology is a very real 'thing', and you can find examples in
almost every steam engine collection and museums.  Folks find solutions fo
hauling longer and longer trains --- even continuing into today----using
radio-controlled, mid train DPUs... Trains approaching 2-miles long..  
With turbo chargers producing today's equivalent of steam locomotive 'superheating'.  



Edited 6 time(s). Last edit at 01/17/23 10:14 by wcamp1472.

Date: 01/17/23 08:05
Re: Camelbacks
Author: 4451Puff

There were safety issues too. There are photos of instances where the main drive rod broke and swept one side of the cab (and anyone inside of it) clean off the boiler. 

Desmond Praetzel, "4451 Puff"

Date: 01/18/23 02:49
Re: Camelbacks
Author: Evan_Werkema

LarryDoyle provided an explanation in these old threads:


A Wootten firebox in and of itself doesn't require a Mother Hubbard cab, but at the time Mother Hubbards were being built, most conventional steam locomotives had "deckless cabs."  The firebox extended nearly all the way through the cab, the engineer worked in a cramped space beside the firebox, and the fireman did his job from the tender's deck.  The Wootten firebox was too wide to place the engineer beside it, so at first, the designers kept the deckless design and simply moved the engineer's cab ahead of the firebox.

The Wootten firebox wasn't too wide to see around if the cab was positioned behind it, so when steam builders eventually started adding trailing trucks, extending frames, and placing the cab behind the firebox instead of around it, a number of locomotives were fielded with Wootten fireboxes and conventionally-placed cabs:


Date: 01/18/23 12:50
Re: Camelbacks
Author: livesteamer

The ICC banned the construction of camelbacks around 1918 allowing a few exceptions until about 1920 or so.  By 1927, the ICC forbid any more orders for camelbacks. The last recorded run of a camelback engine was September 24, 1955.  CNJ #774 (4-6-0) made a return trip from Jersey City to Jim Thorpe, PA.  By March of 1956, nearly all had been scrapped.  I think there may only be 5 left in existence.  The St Louis Transportation Museum has 2 examples--Lackawanna camelback #952 and B&O #173.  The Strasburg had a small Reading 0-4-0 #1187 on display that is now under the care of the Age of Steam Roundhouse Museum in Sugarcreek, Ohio. I believe it was their first operating steam engine in the "modern" era of the Strasburg.  The B&O Museum in Baltimore has 2--CNJ #592 and B&O #217.  As an aside, there are a number of camelbacks operating in the
1 1/2" scale include my 2-6-0 CNJ engine. 

Marty Harrison
Knob Noster, MO

Date: 01/19/23 15:28
Re: Camelbacks - Safety Issue
Author: LarryDoyle

4451Puff Wrote:
> There were safety issues too. There are photos of
> instances where the main drive rod broke and swept
> one side of the cab (and anyone inside of it)
> clean off the boiler. 
This issue has been raised as an objection to the camel design for over a century.  But, I just don't understand why.

Would you rather be in the cab of the 698 if it breaks it's No. 2 drive pin, or the 955 if it breaks it's main drive pin?  (Or, a rod near the pin.In either case, you're gonna get hurt bad.

(Not that I actually like Camels.  IMHO they're UGBUTLEY.)


Edited 1 time(s). Last edit at 01/19/23 19:34 by LarryDoyle.

Date: 01/20/23 05:09
Re: Camelbacks - Safety Issue
Author: LocoPilot750

Strange as it sounds, in days of yore, Santa Fe even had a camelback. I don't have a photo, but there is one in Worley's "Iron Horses of the santa Fe Trail" on P. 233. It was a 4-4-2.

Date: 01/20/23 10:31
Re: Camelbacks - Safety Issue
Author: wabash2800

LIke anything else, the look could grow on you. One could argue that cab-forwards are ugly too.

Victor Baird

LarryDoyle Wrote:
> (Not that I actually like Camels.  IMHO they're
> -LD

Date: 01/20/23 15:30
Re: Camelbacks - Safety Issue
Author: LarryDoyle

wabash2800 Wrote:
> LIke anything else, the look could grow on you.
> One could argue that cab-forwards are ugly too.
> Victor Baird

Well, a camel IS a cab-half-way-forward..... <G>

Date: 01/21/23 18:34
Re: Camelbacks - Safety Issue
Author: Evan_Werkema

LocoPilot750 Wrote:

> Strange as it sounds, in days of yore, Santa Fe even had a camelback. I don't have a photo, but
> there is one in Worley's "Iron Horses of the santa Fe Trail" on P. 233. It was a 4-4-2.

Indeed, 4-4-2 738 built by Schenectady in 1889, based on a very similar locomotive called the A.G. Darwin patented by George Strong and assembled by Hinkley in 1886 (these two engines were reportedly the first 4-4-2's in the US). The engines didn't have Wootten fireboxes, but a pair of cylindrical Fox patent fireboxes side-by-side, which like the Wootten was too wide for a conventional cab behind it. Santa Fe wasn't overly pleased with the engine's performance, and Topeka "rebuilt" it into a conventional 4-4-0 in 1892. The builder's photo and a bit more on the locomotive is in this old thread:


See also: https://utahrails.net/loconotes/strongloco.htm

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