Articulated Locomotives (HO Virginian 2-8-8-2)

Watash, what's all the crud in the valve hole castings? The photo of the No. 2 driver and crank showed up as a red X and I know that would be an interesting picture.

 

Fitz, when we make the wooden sand casting patterns for a foundry, you have to be able to remove the wood pattern after the green sand is packed and tamped in the "Mother" sand frame, so "draft angle" allows the wood to be lifted out. For the interior (hollow part) of the steam chest, a "core pattern" is made to form the sand that will take up the space that would otherwise fill up with molten steel. The holes we want to cast for cylinder and valve chambers would break off and pull out or crack loose and maybe slip out of alignment and ruin the poured casting. So cores are made to place in the "mother" mold, (Mother forms all of the outside half of the steam chest that is on the floor)and has all the core alignment cavities in it. Rods are included in the cores for support, that also supports the interior cores. One end of these rods stick up out of the top of all these cores. When the "Daddy" half of the mold box is put on, the green sand is packed and tamped tight, thus holding this end of the cores steady, and forms all the outside of the top half of the casting.

Core sand is mixed with molasses and baked in an oven to harden it so it will hold its shape including the rods, so it can be handled for assembly into the mother mold, and during tamping in the daddy half. Then the whole thing is baked again.

After cooling the wood framing around the outside of the mold box is stripped away, and the whole thing is heated up around 1,200 degrees ready for pouring. In the mean time the steel "pour" has been melted and poured into a huge ladle that will be tipped over to pour the batch of molten steel into the sand mold. The mold is allowed to cool a little at a time until it gets to room temperature, then a crew comes in with air hammers and breakes up the sand to remove all of it from the casting. This can be a real job, because all the core sand has to be removed from the inside too, and that usually has to come out through a rather small hole.

Huge vibrators are sometimes attached to shake the sand so it will fall, or can be blown out. All the sand must be removed, even sand blasted out of and off of the whole casting. Then it is inspected for flaws.

If a non-repairable flaw is found, the whole casting is scrap, and must be remelted! You don't want to have worked on that job if that happens!

If the casting is stamped "accepted", then it goes to the big machine shop where all the big holes are bored on a Bullard Vertical Boring Mill, then all the small holes are drilled and tapped.

Then it goes to a huge Shaper, or Planer for facing to fit cylinder heads, valve heads, and the boiler on one side, and the frame on the other.

There is lots more, but that is the general Idea.

The rods you see in the photo, have to be torched or bent to remove them yet, but all are loose.

It is all hot, hard labor too, but fun as all get out when you see the engine roll out of the roundhouse under steam!

 

Watash, thanks for that explanation. I have made small sand molds for casting, but nothing on the scale of a locomotive steam chest. The No.2 axle photo came through, and you young guys take a look at that. Is that some machinery, or what? I also appreciated your explanation of the way steam locomotive cylinders are set up. Many others have tried to explain that in ten million words or more, without success. Yours is great. "Top dead center" is something most younger people have never heard nor will understand.

 

Watash, & Fitz,
I understand alot of that and I will say if a steam chest was poured and done up and wasn't satisfactory. you may get a pink slip and told to pick up your pay ... And then see a employment wanted add somewhere for the same job you just got fired from. HA! Anyway, What really interests me is the fact of the different valve gear and so on to the 3 cylinder loco's. Its just different from what everyone's used to and seen alot ...... I'd just like to see how that looked and what it was like... VERY INTERESTING.....

 

The term "top dead center" came from the early vertical steam engines used in the mines. They used to have to pry the crank shaft off center in order to get the engine to run, and even then sometimes the engine would turn part way, and the load would cause the engine to stop almost on top dead center, but then the valve would reverse causing a power stroke in reverse! Many boilers were blown until a fly wheel was installed to keep them running in one direction.

The Gresley type valve gear has been around a long time, first developed and perfected in England, and also used on the old steam ships that had three cylinder steam plants, and man they were BIG!! If you have ever heard a shay engine run, or heard one on a video, it is the same sound as the 4-12-2.

On a piece of paper, draw three small rectangles side by side vertically standing in a row to represent cylinders. Draw a curved line from the center of the top line of the cylinder on the left, to the center of the top line of the center cylinder. Now draw another curved line from the middle of the curved line over to the center of the top line on the right hand cylinder. Now, in the middle of the long curved line draw a small dot to represent a pivot. Starting with the left cylinder, number them (1), (2), and (3). 1 and 3 are the outside cylinders of the engine, 2 is the third central cylinder.

You have just drawn the basic Gresley valve control mechanism. Here is how it works:

As the wheel rolls, the piston of cylinder 3 moves foreward 1/3, the long line pivots and shoves the valves 1 & 2 in toward reverse. Due to the 120 degree timing and positioned on the axels, clyinder 1 will start moving foreward next 1/3 which will push valve 2 back putting pressure on the 1/3 stroke. As 1 gets to the end of its stroke, and 3 is in full pressure at 1/3 stroke, 2 is pulled out, moving the short line out, now causing the long line to pivot, shoving 3 into reverse on the down stroke, completing one half revolution. 3 will come out, shoving 1 in, 2 will come out shoving 3 in, completing one full revolution. Simple. It is a very thoughty design. The idea he had was to have at least two cylinders performing work at all times, supplying a positive push at three places around the circle coupled with three pulls around the circle, or 6 chuffs per revolution. You may have to draw it out isometrically to visualize the action caused by the three points around the wheel and what happens as those three points rotate, and why the third cylinder had to be on another axle.

It reduced the tendancy to twist the axle (like the front axle of a wagon) by having some equal pressure on both wheels. American engines have one cylinder pushing, while the other cylinder is pulling, which really makes the axle want to make a left turn. If the frame didn't keep the axle aligned, it would turn. Since it can't turn, all it can do is rotate foreward, but under quite a strain.

American engines had more of a Bark to the exhaust, where English engines have more of a purr sounding exhaust. Now you know the basics.

[ 27 July 2001: Message edited by: watash ]</p>

 

THANKS Watash!!! You know of all the younger guys on the board I probably am the one one that understands exactly what you just sai! I've studied steam motive and how it works along time in school and out and that saying about the axle turning but can't because of the frame is very real... Thats why the American loco's would twist off or Shear off axle offen because of the push pull motion on the axle itself.

On the "Top Dead Center" that was because on the vertical boilers not having a flywheel to complete the wheel travel that it would jam and somehow the engineer would have to roll the loco in reverse to get it to where it would restart motion and not jam. It would stop exactly "Top Dead Center" of the valve and it didn't have but one rod pulling and one pushing and was a bad situation to restart motion to continue on moving after a dead stop. If my memory serves me right...... Thats when the mechanical engineers started realizing it was hard on axles and wheels and they were nontheless, it would and did twist off axles and made some terrible repairs to be done!

 

Youre right John. It was only a problem on the single cylinder steam donkey engines, and early mine pumps though. You couldn't roll them off center. You had to shut off all steam and empty the steam chest, then pry the crankshaft off center so it would run. This was also true of the live steam toys. They would run foreward or reverse depending upon which way you started the wheel to spin. I have one that wont really slow down like I would like it to, because the way it is designed, it will stall at too slow a speed. They have too much dwell at cut-off, I'll re-work the valve so it will just creep.

 

Watash,
So you got some "Live Steam" toys too??? I have 3 that work and one that was given to me that needs some work do to it as well. I'm not sure but you may have heard of this in Pennsylvania.... Its called "The Farmers and Threashermans Jubilee", held in New Centerville, Pennsylvania. Its a farmers thing I know but, Its got alot of things their everyone on this board would love! HA! They have 2 buildings that have old Alco RS-3 diesel prime movers in and they run!!!!! Also Tractor pulls... Not like you would see at a local fair but.. STEAM trackor pulls! HA! I mean this is one thing in my area thats out of the way for a railfan or buff....But has a ton of things included in it, in conjunction with railroading and all of us here!!!!!

But anyway... This Jubilee is where I got the 3 of the small single rod/stroke real true steam working model that will fit in the palm of your hand. I got them as a young boy and they really did then interest me, at that time I was already into model railroading (collecting more or less at the time), but anyway thats what got me into steam loco's as deep as I am now.... I do accaisonally run those live steam displays just to bring back the memories from the days that I got them... However, the last one I got that was a gift for my birthday (September 1st btw) the Jubilee is the first weekend in September every year so... But anyway the last one I got for a Birthday gift was formatted as a steam loco was and has a set of 8 wheels, like an 0-8-0, just made upside down from what an 0-8-0 is... But has all the valve gear ecentric and linkage and main rods etc... Anyway I run that one most of all... Being if I do it right it would be a running live steam scale model 1/48th, O scale 0-8-0, and yes to everyone with the question, are you going to make it an O scale 0-8-0, my answer is yes. once I can get a boiler and cab and things of such for a body I plan to make it an O scale 0-8-0 live steam model. I'd almost bet it will out pull any O scale electric models!!

I have used a smaller one to run a small 12 volt DC generator on my layout as a conversation piece, but recently took that down off the layout being I have some seals to replace and maintenece to do on it at the moment.... I had that all detailed up as a power plant for a small town on my layout and very, very realistic! I had it to where it would keep a steady 12 VDC charge going to a set of 12 volt NiCad batteries to hold power to light up my houses in this little town I have on my layout. It was monitored off of a gauge on my control panel to tell me how high or low the charge is in the NiCad batteries and would pop a red LED on if It was getting close to an over charge and that would cause a block to redirect power elsewhere, and or shut down the steam display to quit charging the generator to the batteries.

I have to wait till this September to get to the guy that sold it and also sells parts for it and the rest of them so I can rebuild it.

But I will admit they are some little toy that you just don't let set around and not do anything with beside collect dust... I try to keep mine in prefect running order as much as possible..... And are a fine conversation piece, when fellow model railroaders are visiting....

[ 28 July 2001: Message edited by: 7600EM_1 ]</p>

 

[ 29 July 2001: Message edited by: watash ]</p>

 

John, this is an articulated, the front wheels turn, see? Its powered by live steam, and doesn't get flats.



[ 29 July 2001: Message edited by: watash ]</p>

 

Alan, thanks for posting that diagram. And Watash, it is laid out exactly as you described. We know we can always count on you two to assist in these technical discussions. This thread has certainly turned into one, and I love it.

 

Sounds like a boiler blew up there in ohio..Sad indeed.!!

[ 30 July 2001: Message edited by: bnsf4354 ]</p>

 

Fitz, you remember old Art? He used to say, if he didn't know how to word an answer, he could always snow them with technologie!

BNSF4354, what boiler blew up in Ohio?

Here are some other shots of the 1915 Port Huron steam tractor. It develops about 18 horse power, and still runs today! Some of them have a whistle that sounds just like a train whistle. That is how they called all the harvest crew in to eat for lunch, and when to quit for the night, etc. These old babies could rip along at about 3 to 5 miles an hour under a full head of steam!

 

Watash,
Those ARE exactly the steam tractors I was talking about! HA! Anyway. Here in PA theirs a farm that still runs them each and every day for their regular use believe it or not! Anyway theirs a Jubilee here in PA just for those as well and amoung other interesting things... I try to attend it when I have the time and to get away on a days break or a 2 day break from reality and the shop... I'm hoping to go this year to get the parts for my little steam toys I have, so I can get them up and running again... If I remember my camera, I'll get some pictures of the Steam tractors.... And I'll post 'em on the board here for everyone.

[ 30 July 2001: Message edited by: 7600EM_1 ]</p>

 

Watash, evidently the boiler of a "steam traction engine" blew up at a county fair in Medina, Ohio as they were firing it up to display at the fair. Three were killed instantly and a fourth person died on the way to the hospital. The explosion threw "shrapnel" 350 yards. No one knows what happened as those operating the machine were all killed.

 

Thats sad... specially durring a fair.....

 

Gregg, I have seen it on the TV News here, and from what I hear, and see of the engine, my guess is he got distracted, time and water passed, and he didn't open the injector. Some of the later ones had a sort of automatic, but you still had to pay attention to the crown sheet. It appears that the rear end of the boiler blew off on one side. That recoil blew the people away and turned the engine over. One newsman said they had been running it, and were driving it into position for display. That means it was already fired up. With all the other fellows on board, all talking, it would be about the same if you were trying to drive through downtown Dallas in rushhour traffic!

Yes, it is tragic.

 

I think those Camelbacks are nice...in a different kind of way.

From what I have read, that was not really a good design.

I believe the book had a title along the line of "Great Rail Disasters" but I cannot remember it now...It has some great, erie photos of brokenup wooden passenger cars, telescoped Heavyweights (the ones they all said could never possibly telescope), and finally, blownup boilers...might be a great idea for one of those old Tyco plastic boiler 2-8-0 tender driven steamers.

And also in that book, a section on blown rods(inwhich the rod unhitched itself from the driver), and most of the fatal cases occured on the camelback inwhich the drire rods were directly blow the engineer...perhaps on of the reasons the roads didnot use them much.

 

Benny, there were a number of problems with the Camelback design, but the mainproblem was the lack of communication between the engineer up in the cab and the fireman clear back at the tender. In bad weather the fireman had to make his way along a foot board to the other side of the boiler and into the cab to get warm or dry. Many times he could not watch his fire from the cab, and water got low, his fire went out, and some firemen were even thrown off when the engine changed speed. It was really a bad design. The engineer was right beside the hottest part of the boiler too. The rear cab or front cab was much better for both men.