Steam & Excursion > American Freedom Train brain trust.

I have taken hundedths maybe thousands of pictures of the #4449 and the people who started with the AFT in 1975 all the way up to Doyles merry band of miricle workers of today.  It would be an understatement to say that the #4449 is probbly the best maintained operating steam engine in the Country.  The team meets at the enginehouse several days a week but not during the weekends.  They take a lesurely break for lunch and then back to work for a few hours befre heading home. THIS PHOTO is credited to Ron Beran. It is similar to one I have and I uploaded the wrong photo by mistake.  I regret the error. Image one: Doyle and Jack have been friends for almost 50 years going back to the decison to pick the #4449 and its first restoration at the Hoyt Roundhouse. After the last weekend of the Santa Trains in late December with the engine in the enginehouse; Doyle and the steam crew performed a proceedure where by the blow compressed air into the boiler and steam lines to prevent rust from forming during the winter hibernation. The first thing is to take is the pistons from the cylinders to create a path for the water to exit the #4449. The next series imaages were shot on Monday December 20th and show the process.



Edited 3 time(s). Last edit at 01/28/22 12:46 by weather.

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Image #4 is Bobby Slover, the youngest of the original AFT crew who started at 18 years old! Why started volunteering 1975, I was 29.   Image #5 Using a forklift, the piston and cylinder are extracted. #6 after the work is done, back to the break room for lunch.  Text and Photos by Mike Pechner, Copyright, 2021, "All Rights Reserved."



Edited 1 time(s). Last edit at 01/26/22 22:50 by weather.

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Technical clarification....

What's removed are the spool valves, one on each side..
The 'pistons' are much larger, below the valves, and power the drivers,.
Picture 5 shows the spool valve hanging from the the fork lift, and
you see why the common name is "spool valve", also calied
piston valves, as opposed to the box-like slide valves --- as used
on older locos,  before superheating was perfected.

During blow-out sessions, the main advantage of removing the spool valves
is greater air flow through and out the superheater units... Compressed shop-air
fills the boiler shell, and at higher pressures, you get a greater air volume & 
flow-rate in order to move all the standing water out of the units..

Type E superheater units each have two ends and 4 passes down 
four superheater flues.  There's an upper branch of two passes and 
two lower branches to each 'unit'....They divide at the vertical parts 
of the units---  at the front flue sheet....

With restricted air flow, ( caused by four varied port openings
of the spool valves)  standing water from the two upper passes
is only moved to the point where the upper and lower tubes combine,
just below the header casting.

That is at the vertical series of joints ---- and water, being heavy---
simply gets blown into the lower two passes... resulting in
the greatest air flow out the two upper passes, and the water,
being heavy, gets moved into the two lower passes...

By removing the spool valves, it allows the greatest air flow volume and 
pressure differential across all 4 passes of each unit --- thus ensuring
the greatest air flow from the wide open throttle.poppets that are in the same 
header as the units are attached to.

The throttle is downstream of the units, and when hot, the steam flows through
two parallel paths -- each path has two passes to bring the steam to the 'hot end'
two times.

The boiler water, even at 400 F, is colder than a hot fire --- at 3,000 F...and the
flames and hot gasses get cooled-off after about 4 feet down the flues.  The small 
flues break the gas flow into a couple of hundred flues, and the small paths in each tube
gvie up their residual  heat vert rapidly.

The units add heat to the steam only at the the return ends closest to the flames---
so, Type E units deliver hotter steam to the pistons....compared to Tyoe A units.

Another factor involved is the dwell-time that the steam gets held in the path of the hot flames 
of the fire.   Very hot superheater temps mean fewer H2O molecules are used in each piston stroke.
Superheated steam has the invividual molecules more rapidly vibrating and with greater amplitude...
and greater spacing from neighboring, highly excited molecules.. so there is less quantity [ weight]
of H2O molecules per piston stroke --- while also preserving great piston pressures.
Expanding steam always cools-down proportionately to the expanded volume.

Hotter steam means that Doyle can close down the throttle, while getting very hot steam 
to the pistons.   The steam temps at the spool valves will be near the temps at the
hot end of the units.   The more narrow port openings of the valves restricts the amount of
steam admitted  at the pistons, and frtther lowering the temperatures --- expansion towards
the pistons is a cooling process .  The closed-down throttle positions gives greater 'dwell time'
to the steam in the hot ends of units, thus, gaining more temperature. 

That's the advantage of superheating --- you can reduce the throttle opening ( and commensurate
steam/water consumption) yet maintain the boiler pressure all the way to the spool valve ---- and with
shortened admission times ( and narrower port openings) the volume admitted per stroke is reduced..
..but, STILL superheated, well above its point of condensation --- exerting 'work' against the piston
all the way until the exhaust port opens...  An engineer running with valves at  a 28%to 33% cutoff,
you get power to the piston past 85% of the piston stroke!!!
 
"Temperature" of steam means greater separation of the vibrating molecules...
hotter steam at the pistons means lower volume ( quantity of molecules, per stroke)
and lower numbers of rapidly-vibrating molecules per piston stroke.   

The lowest state of molelecular vibrating activity of H2O is the liquid state, and the solid state.
So, when 4449 is cruising, Doyle adjusts the valve travels to provide good cushioning
of the pistons, and uses the throttle to close-off the steam flow to get the greatest dwell-time
for the steam at the hot return bends of each 4-pass unit...

The valve travels, and port width openings, are reduced  ( by the valve gear's cut-off setting)
at the closed-down ports of the spool valves.

During the compressed air blow-out procedure, you want the greatest air flow possible ---
so, yank out the spool valves --- an blow ALL the water out of the units.
Any Water left standing in the units will eventually pit and rust through the units from 
the inside...

Another crucial element  in improved air flows and volumes, is the removal of the
front valve covers.   The removed round covers allow the spool valves to be yanked, 
and the covers must stay off ---- to get the greatest air flow through & out the valve ports.
See picture 4, above.

Great clouds of cold water and mist will come whistling out the wide-open valve chambers.
You make repeated 'high pressure' blows until you're satisfied that she's as dry as you can get.
Joe Karal always advised building a hot, wood fire in the firebox after the blow-out session...
for 30 minutes or so.  With plenty of air through the firebox.. Your mileage may vary.

Type A units are one tube-each,  folded 4 times down each 5" diameter flue.
Since it's a single-pass ( per unit), standing water is blown-out more easily with locos
equipped with Type A units.  So, you won't need to remove the piston valves 
to get the air flow you need to remove the standing water.... but, it couldn't hurt
to do it on the simpler design of Type  A units.

Question: Do they blow-out the units inside the building, or do they do the  blow-out
process outside?

​W.

( not proofed, yet)...)
 



Edited 10 time(s). Last edit at 01/27/22 12:56 by wcamp1472.

Since 1522 has Type A superheaters, our routine was somewhat simpler.
Blow down the engine hot, cap everything and go home.   When everything has cooled, we would charge the boiler with air and blow out  all of the appliances and lines.  Rechage and then open the throttle and cycle the power reverse back and forth a few times, recharge and run her back and forth until she wouldn't move any more.  Pull the bottom washout plugs and screen the openings, cap the stack and go home for the winter.
Never had a problem with anything freezing (she was stored outdoors),  never had any superheater issues since she has a dome throttle and come Spring she was fit as a fiddle.
Two small freezing issues were the valve on the back of the tender for the aux tender water feed and a small crack in the oil firing valve.  That was when I accidentally discovered that Laclede Gas in STL used the exact valve at their entry point into our shop.   I contacted them and got a new valve to replace the old one and then brazed, remachined the old one as a spare.
Not bad for being in service from '88-'02.

Many, many thanks Wes for the explanation! And the correction.  I was hoping that you would add to this. Of  course you and SR are part of the "Brain Trust" and without your exxpertise the #4449 and the AFT would not have been as succesfulas it was.

It's also nice to see some impromptu photos of the crew during some down time too. Great photos and commentary. Thanks for sharing.
 

All done outside, Wes. 

Good!

( That was my perception)...


​W.

Do you "blow dry" the piston cylinder seperately?

Typically, the cylinder drains are OPEN; ( commonly called 'cylinder cocks').
thus, there is no 'standing water' accumulation, as can occur in the
"units"...

4449 has steam-closed cylinder cocks, operated by the engineer;
thus, with no steam applied, they are always open.... draining any accumulating  water.

You would want to pay particular attention to fully draining the piping
and supply to the booster engine on the rear trailer truck axle....
as well as ALL the steam-operated appliances, water hoses and piping.

​W.

( There are types of cylinder cocks used on later engines that are a ball
check valve  [horizontal] Type..  These are opened by an air-pressure piston and plunger
that pushes OPEN the ball check when operated by the engineer.

 I've had problems with that type in unusual circumstances, so I always removed that cock
assembly --4 per locomotive---during winter storage of engines with air-operated cylinder cocks...

Reading T1 engines, like 2100 and 2102 are protected with steam-closed cylinder cocks...)..



Edited 2 time(s). Last edit at 01/27/22 20:10 by wcamp1472.

Very nice to put faces on names thanks for all the very good photos.

Mike, thanks for the nice pictures of the crew and my family at work.

Scott Gordon

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