Firebox Replacement

Oil burners were subject to more thermal stress over their lives than coal burners. Shut off the firing valve in an oil burner and all you have left is whatever thermal inertia is stored in the firebrick...which is not much. Consequently the temperature in the oil burning firebox can change rapidly, setting up mechanical stresses.

In a coal burner the massive amount of "thermal inertia" present in the hot bed of coal meant that a coal firebox changed temperatures much more gradually. Thus they were not subject to the same thermal-induced mechanical stresses that an oil burner was.

Interesting; I never knew that.  Thanks.

i can see grates and brick arches being replaced within the lifetime of a boiler, but are you saying the entire rear (firebox) section was actually cut off and replaced?  i'm not sure if i buy that and i've certainly never heard of it done with a scale live steamer.

No, the entire firebox was not cut off. The internals were what was worked on. The various sheets - side sheets, door sheet, crown sheet, throat sheet, etc. - were replaced or repaired as needed, along with the staybolts used in those areas.

Sometimes the thermic syphons, circulators and arch tubes would also have to be replaced.

ok, i can see the firebox area certainly getting more scrutiny than the rest of the boiler on inspections.  in the old newsreels, i always see those white coated guys who carry around the hammer listening for flaws while tapping at the stay bolts.

scale boilers certainly have some benefits due to their size.  most operators running 1:8 scale use some sort of chemical treatment for their water.  i don't suppose full scale live steam has that opportunity though i imagine with the infrequent running of #765 and similar excursion locomotives, they get washed out fairly often(?)

thanks for the information.

cheers...gary

Real steam locos received water treatment too.  Just think of Santa Fe running through bad water areas of the west.  Somewhere in one of my books is a photo of the fireman dropping balls of chemicals into the tender tank.

ChipR

EVERY railroad steam locomotive, including the 765, uses water treatment chemistry of some kind. It is a "witches brew" of oxygen scavengers, anti-scaling compounds and PH control. We also regularly measure the dissolved solids in the water and determine our blow-down schedule accordingly.

The water treatment chemistry for steam locomotives running over the same routes all the time, using the same water all the time, could be very finely tuned. Today, a main line steam locomotive like 765 may take water while on the road at dozens of different locations. Consequently we test the water EVERY TIME we take water, to measure the PH and several other factors that affect how we will treat it. From the results of those tests we decide how much of which chemical to use when treating the water.

The boiler is washed on a 31 day schedule. Planning for boiler washes when on the road is just one of many operating logistics that have to be carefully planned when going on the road with a steam locomotive.

What effect does grate area and free gas volume have on this?  If any?  I'd imagine a smaller loco, such as 2-8-0 or 0-8-0 would have somewhat lesser stresses than a Texas type or big articulated.  I'm guessing that firebox interior operating temperatures would be fairly close, but that size could have an effect, as the components expand and contract.  

The size of the firebox is NOT the issue between oil burning and coal fuel. Remember, in a coal burner there is a REAL FIRE, with an enormous heat sink of red/white hot coals, and that coal fire reacts relatively slow to changes in throttle, cutoff, draft, and the rate of feed water input.

With oil burning steam locomotives, the is really no fire, just a flame off the burner, and the size of that flame changes instantaneously with throttle and cutoff changes. Those rapid changes require that the Fireman make just as rapid changes to the firing valve which controls the oil to that flame.

Thus, load and temperature changes happen VERY quickly in an oil burning firebox, as compared to a coal burner, and the resulting stresses on all the interior steel sheets is NOT conducive to long life. Therefor, most railroads that operated oil burning steam locomotives tended to schedule renewal of internal firebox components at ten years of service. 

Understood, about the coal vs oil fuel.  I was thinking in terms of loco size within the context of coal OR oil fuel.   However...this makes me wonder about the Big Boy oil conversion back in the late '40s, IIRC.  Challengers are OK with oil...and BB is not?

I'm not understanding UP's logic of attempting an oil conversion on the 4000 class if they didn't plan on doing more of 'em if it worked well enough.

I know it isn't really my fault, but I'm sorry for asking the trailing truck question.  I didn't realize I could start an event that will forever be in history books. 

 

Also That's makes me wonder, should I even try asking why Marx Steam engines don't work with Lionel Switches?

LOL!  

Max, you have nothing to apologize for! Your question on that "other" thread sparked a lot of good discussion...and some classic nit-picking.

There are some in today's world who simply cannot accept a definitive YES or NO kind of answer. For them, everything is open to interpretation and only exists in various shades of gray. These are the same types that, if given a chance, would argue with you about whether the sun REALLY rises in the east.

It's a lot of Bullhocky.

Now back to the firebox...

Since you asked, I'll take a stab at this one! The integral gears on the backsides of the drivers of Marx Steamers are very large- all the way down to the wheel tread, if not beyond. When you try to put that wheel through a Lionel switch, the gears catch on the inside guard rails and pop the engine up, usually derailing it. Lionel engines have smaller gears, and they are not integral. The combination allows the engines to traverse the switch smoothly.

Chris

LVHR

PS I have enjoyed both threads, and have learned some things. Please keep asking the questions!

I think it mostly had to do with the 4005's fuel consumption.  The UP would of had to install line side fueling/storage tanks for them and since that bunker C needs to be heated so it will flow that would have been some expensive upgrades for the UP. 

Chris is exactly right. The main reason the the UP Mechanical Department experimented with the 4005 on Bunker C, was two fold: A) an impending coal miner's strike, and B) to see just how to make the conversion vs. internal firebox issues.

Once some of the uneven heating issues, which cause many weeping stay bolts, were overcome, the 4005 would up firing and steaming VERY well (a number of crews indicated to me personally, that the 4005 steamed & fired better as on oil burner than ANY of the oil fired Challengers!). I can tell you from experience, that 3985, as an oil burner, was NOT "easy to fire"!!!

The biggest down fall of the 4005 test as an oil burner was, she used such massive quantities of Bunker C, she couldn't get all the way over Sherman Hill with a full tonnage train. The UP was NOT about to invest in a steam heated Bunker C fueling station, on Sherman Hill!

Rich and others, appreciate the full scale info.  have to say that with a club or even at a visiting track, scale boilers at least typically start with somewhat treated water.  i can just imagine the problems that might be incurred with "take-what-you-can-get" water stops.

cheers...gary

In the real railroad world of regular service steam locomotives, water was DEFINITELY a serious problem. For example, the UP used to do boiler washes every 15 days, instead of the ICC required every 30 days, due to such "bad water" across Nebraska.

In todays modern "traveling excursion/Public relations" steam locomotive tours, there are two basic ways to handle todays water situations:

1) The Union Pacific Steam Crew treats the water in the tenders, based on sampling the water at EVERY fire hydrant that water is taken from.

2) The SP 4449 crew tests the boiler water 1 or 2 times EVERY day, and adds chemicals to the boiler, through the injector, in order to maintain a certain level of treatment. 

On the small steamer front, firebox replacement is rare, but not unheard of.  I happen to own a steamer that has had the firebox replaced.  The main difference between small steamers and their full-size counterparts tends to be the level of maintenance they receive.  Small steamers that need firebox work typically suffer from a lack of boiler washes, therefore the boilers will tend to get thin around the mudring, bottom of the boiler barrel and bottom of the front fluesheet - all places where sediment has settled and retains moisture.  So, many times when the firebox needs to be replaced on a small boiler, the barrel and front fluesheet are in equally bad condition making it necessary to replace the entire boiler.  A well maintained small boiler will have the same long-term issues with steel tubes and the firebox that the full-size locomotives do.

On that note, I have two locomotives on the property that are awaiting restoration, one built in 1907 (in the process of restoration), the other built in 1899.  Both boilers are in bad condition and will be replaced rather than rebuilt.  They exhibit the classic problems that I described above... 

Wash those boilers.... 

I guess I could look it up - how do you wash small boilers?  Is there some solution, or do you just run clean water through there?  Maybe I should just sell the things, and not worry about boiler corrosion.  The largest one is steel with steel flues and drypipe,and is  stored as dry as I could get it.

During a Noon Shop Tour on the Strasburg Rail Road, my host mentioned that the Strasburg tests water every day to determine how to treat it and protect boilers, as Rich and Hot Water posted.

The Santa Fe had water treatment facilities connected to water tanks in the desert, where alkali and other impurities were chronic problems. Untreated water could cause "foaming." Bubbles would form but not break. They carried water through the throttle valve and into steam chests and cylinders, where all sorts of trouble began.

The Santa Fe was an early convert to diesels, because diesels ignored every water tank on the system. That eliminated a BIG problem.

I once saw ex-Great Western 2-10-0 No. 90 spotted behind the enginehouse being prepared for her 30-day boiler inspection. Water was gushing out of her drain plugs. She was cold, of course, but that was a startling sight.

bob2, you can keep your locomotives. Be grateful that your feisty fellow Forumites pointed out this potential problem before you had to deal with it after it arose.

The SP had a difficult time adapting locomotives to oil firing for the reasons stated above. That road had the resources to fix one damaged firebox after another. But that sure isn't the case today.

quite a difficult question to give a pat answer to without knowing any operational history of your locomotive(s) and construction.  i notice you are in Ca, so if you'd care to send me an email, i will see what i can do to either help you out or point you to a group who would likely be glad to give you advice or lend a hand in testing your equipment.

cheers...gary

The Chula Vista group is always willing - I just spend entirely too much time at the airport to do any live steaming.  The 1" scale stuff has all copper boilers, and the big 1.6" scale SP Pacific was blown dry on a low humidity day about a quarter- century ago. It will have to go in the next decade - it is simply too big.

I note that running a steamer is a lot like flying, or sailing, or bricklaying.  You have to learn a skill set.  I have never developed that particular skill - every time I would turn the injector on, the fire would go out.  I had to move the blower to a different manifold. Then I went back to flying - I am fairly good at that.

interesting... in retirement i went in the opposite direction giving up flying.  getting somewhere faster isn't as much of a priority now, though when i'm driving out to Las Vegas, sometimes i do miss the 50 minute vs five hour transit time.

1" scale is a tough sell in the southwest.  i only know of three California tracks, the closest to probably both of us being LALS.  personally i'm trying to get a 1" scale Pacific restored to operating condition, but in 7.5" gauge i prefer the smaller 1.5" scale equipment.  being most familiar with 1:48 O on 1.25" gauge may have something to do with that.  

good luck...gary

Getting somewhere faster is not my plan - I have lifetime free travel on American, and that is fast enough.  I enjoy the maintenance of the skill, and enjoy turning a wrench.

I have never been much for running trains, preferring to make them run flawlessly for a couple of loops and then displaying them.  That is not true of the live steam - I get it to run on air, and then I am off to the airport.  Yesterday I did five landings and seven slow rolls.  Today I will do some spray painting and await the safe return of a student on his first cross country flight.