It’s all like very fragile plastic spaghetti Rooster, I just throw it away.
Great shots Rooster, and great modeling! Did you scratchbuild all that, maybe with some purchased parts?
An operating sister loco of the Joe D has lots of detail to go by, thanks to Wendell at NSRM who sent me pics of her (the Seward). Rumor has it that this is the first loco to go to Alaska.
Courtesy Wendell Huffman, NV State RR Museum
That shelf is off-center! Huh.
Courtesy Wendell Huffman, NV State RR Museum
Sure looks like the LGB, with that saddle tank and boxy cab!
I’m not gonna attempt much backhead detail though, because, let’s face it, I’m pre-screwed, starting with LGB chassis / wheelbase / valve & drive gear / boiler dimensions. But maybe when the Joe is measured and documented (might be this coming spring) I’ll consider a new model (we’ve discussed this dilemma in prior posts, no turning back now).
All fun stuff though!
Cheers,
888:> Cliffy
For this project though, I guess my signature should be:
T:88> Cliffy
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Cliff,
The johnson bar and gauge were bachmann (I think) the rest is pretty much scratch except the bell.
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It would sure be nice if somebody who knows could write a short tutorial about what all that stuff is. For example, “johnson bar” is probably known to everybody here but me, but doing a quick search found this anecdote (not sure if this is what Rooster meant):
When an engineer changed the reverse lever position to “notch” up or down he had to hang on for dear life ! Hence the term originally was “jouncin bar” which over the years morphed into Johnson bar.
I found it awesome when Devon and Rick explained their steam donkey engines to us during the Mik when we had dueling projects. Super helpful for me when I was doing my Surry Parker log loader project.
Cliff: I’m not trying to add to your load, just noting that it would be handy to have a guide to steam engine cab controls.
I’ll do my best Jim. This is a good simple backhead and shows almost all the goodies found on a simple locomotive backhead.
So the “injector” is a steam operated, venture driven, device that “injects” water from the tender into the boiler. Since the boiler has a high pressure and the tender has none, there is a challenge of overcoming the pressure in the boiler to add water. Steam is passed by a venture which causes a negative pressure on the tender feed line. the venture literally sucks the water out of the tender and it increases the pressure beyond that of the boiler and thereby the water can then be injected into the boiler. There are many different styles of injectors. And most locomotives will have two, one on each side that can be operated by either the engineer or the brakeman.
The “Sight Glass” is a simple device that fills with water to let you know how much water is in the boiler. Typically there is a valve at the top, bottom and a drain valve. Water seeks its own level so whatever the level in the boiler it will correspond with with the sight glass. Its a visual gauge of water level.
Working in concert with the sight glass is the the “tri cocks”. They are 3 valves that correspond with the boiler being full, half full, and empty. You open these valves just a crack so they drip. they are also orientated with sight glass. If the stop one drips the boiler is full. If it hisses steam your water level is below that valve. If the middle one is dripping you still have enough water in the boiler for safe operation. When it begins to hiss steam you should be thinking about filling the boiler. The bottom one should ALWAYS drip. If it is hissing steam a boiler explosion is just around the corner. The “funnel” is just where the dripping water from the tricocks goes and drains through the floor and out onto the ground.
The oil can shelf is primarily used to hold oil cans. The oil used to lubricate the steam chests and bearing of a locomotive is very thick. It has to be in order to stand up to the intense heat it is used in without just burning up. So when its cold it does not flow well. So they put the oil can on that shelf to get heat from the backhead to thin it out. Its also a good place to keep coffee warm.
The “throttle” is just that. It adjusts the speed of the locomotive. There is a rod that runs into the steam dome and operates a valve that in turn sends steam to the steam chests and cylinders. As you operate that you increase or decrease the amount of the steam going to the steam chests to operate the cylinders faster or slower.
The brake (I am not sure that is what that is) is where compressed air from the air compressor is regulated to the locomotive and train brakes as long as it it is positive pressure device like a Westinghouse. If it is an vacuum brake system like and Eames, it could be another venture sort of affair that uses steam to create a vacuum that pulls the brakes on. The device that runs that looks similar to another injector. That one on that locomotive is hard to see.
The “Johnson Bar” is the gear shifter. When you look at the steam chests there is a rod protruding from the rear of it that is attached to a linkage. That linkage is then attached to the Johnson Bar. When you move it forward it shifts the steam chests so that steam is operating the cylinders in one direction making the locomotive drivers move the locomotive forward. Move it to the middle and its in neutral. Move it back and it reverses the direction the steam chest delivers steam to the cylinders and drives the drivers the other direction reversing the locomotive.
Some things that are not seen is at least one pressure gauge that tells you boiler pressure. There is also some sort of “turret” on top of the boiler backhead that is nothing more than a device to connect all your various steam operated devices: brake air compressor, dynamo/generator for electricity, automatic oilers, etc. On later locomotives there would almost always be one or multiple hydrostatic oilers. These devices used steam pressure from the boiler to push oil to various places on the locomotive such as the steam chests. It allowed the crew to oil things while the locomotive was in motion. Prior to this they had to stop, grab the oil can, walk around and fill oil cups, and then get going again. The hydrostatic oiler for the most part eliminated the need to stop.
I think I got all the main tidbits that you will see on a simple backhead. Large locomotives have tons more stuff hanging off the back and I have no idea what a lot of it does.
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There are some various levers also. I believe the one going through the floor left center is the dump for the ash pan. As the fire builds ash it needs to be dumped. They usually would pull over a lined pit and pull a lever that opened the pan. But it could also be the dampers that allow air into the bottom of the fire box. If the loco has a sand dome, there is a lever that comes through the front wall that opens and closes the sand dome spouts. The sand dome is either gravity fed or some of them were pressurized with air (not steam or the sand would get wet) and it squirted the sand out.
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Thanks, Devon. Super helpful to me.
Probably should add a not here about boiler construction and how they operate as it makes the tricock and sight glass more understandable. So the back of a boiler is the fire box. Then the main long tube of the boiler is where the water is held. it has a whole series of tubes in it that allow the hot air/gas/smoke to move to the smoke box which is the front part of the boiler where the stack is. As the hot air/gas/smoke moves through these tubes it heats the water. And then it exits the boiler proper into the smoke box and out the chimney or stack (depends on what country you live in as to what you call it). You don’t want to much water in a boiler or there is no head space for steam. Steam expands and that’s what creates the pressure. If you are too full then you won’t have enough head space and you won’t generate enough pressure. You always want your top tri cock hissing steam because if it dripping then your boiler is too full and you won’t be making optimal power. Then there is the operating level where it is neither too full and has not yet dropped below the crown sheet (more on this in a second). this is where the top tricock is hissing and the two lower ones are dripping. This is the sweet spot. Once the water drops to low you start to get to much head space and to much pressure. Once it drops below the crown sheet ( the bottom tri cock) then all the water flashes to steam, the boiler over pressures, and it explodes.
Now I don’t really know what the crown sheet is or does. I hope someone can explain. But you never want it out of the water. The crown sheet is at the rear of the boiler at the firebox. On steep mountain railroads it was not at all uncommon to see locomotives backing down a grade. Sometimes its a simple matter of no place to turn around. But more often it was to keep the water sloshed to the back of the boiler and over the crown sheet. If it went down nose first the water would run to the front of the boiler and expose the crown sheet and boom.
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Thats all I have for now. Thats just a quick down and dirty.
If you fire a ‘LIVE’ steam locomotive, a lot of this will become 2nd hand, and you’ll NEVER question why diesel locomotives took over! 
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So literally it is the top (crown) sheet of metal that forms the top of the fire box. Makes sense. And you wouldn’t want it exposed from the water as it would then super heat and rapidly and uncontrollably increase steam pressure
Makes sense
You mean it’s not because people are lazy/stupid/boring? Diesels ruined trains.
I say that as I am working on my Geep
I support the war on global warming. We need to put an end to diesel locomotives and even coal fired steamers. We need to go back to wood fired locomotives and save the planet
It just might have had something to do with how much maintenance the steam locomotive required…or perhaps how long it took to get ready to go!
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All I heard Bruce was blah blah blah people are stupid
Quite possibly the only thing worse than modeling a diesel freight train would be someone who models Amtrak. . . Even if they do do an excellent job of it.
I think this should be venturi. Spell check, auto correction sucks sometimes.
I know Devon knows how one works because he and I are in the same business, but Jim, a venturi is an hour glass shaped “tube” that increases the velocity of the steam, in this case, and because velocity is inversely proportional to pressure as velocity increases, the pressure decreases and when designed properly can in fact cause a negative pressure resulting in a vacuum.
Now you know everything I know about steam engines 
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Damn engineers who can spell