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Discussion Starter #1
Here is a photo and video of this awesome engine.



Because it is so small we decided to do it in G3 at 22.5:1
To use the LGB rack and its holders, I tried these brass bridges that worked but we would need 200 of them so we are looking for alternatives.


Because the elevation varies by 8 degrees, I decided to make the crown sheet as low as possible thus increasing the water capacity


I then roughed out the chassis to determine the clearances and get some cad drawings of the parts to be CNC milled


And started on the cylinders.


This is a point to point RR which will require RC. Because piston valve are required for the cylinder valves , I decided to kitbash some Ruby parts. Using them, I should be able to have only one reversing valve for four cylinders.
The Ruby cylinders and valves need to be cut down to scale length. I picked up a pair of Ruby valves from Acucraft.
The first step is to cut off the steam tubes as I will need to mount it in the four jaw chuck for machining
.

I could mount the valve in the independent four jaw but one jaw would mar the port side and doing four valves a lot of adjusting would me necessary. Instead, I used two 1/8" strips which were reduced by .002 each on the belt sander. and mounted the assembly in the self centering four jaw.
I had to reduce the body of the valve to .850" but I left the valve part the full length to be able to use the Ruby piston.


Since the valve and piston were cut, I lost the front mounting holes. New holes were drilled out on the mill.




The engines are different on the prototypes but I found one that had covers or cylinders with vertical grooves so I made some in my valves with s 1/8" ball end end mill.


So, here is the cylinder for now.
 

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Another one of a kind, I love it. I never tire of watching your genius at work. I'm a little surprised that you didn't go up to 1/20.3.
 

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Discussion Starter #3
Thanks
Yea
bigger would have been easier but the 22.5 will give it the correct stance with the 2-1/2" gauge.
It actually works out to 22.6 but who is splitting hairs
 

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Bill, it’s off to a good start. Looking forward to seeing more.

If you really want to get down to it, the railway was built to a gauge of 4’-8”, so 1:22.4 would be correct. Somehow, I don’t think anyone will notice.
 

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Very interesting build, i had a chance to ride on the railway 20 years ago, very fun. The cars rattle like crazy since they are so light weight. At least you only have to build one car.

Steve
 

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I tried to ride that in 1996 but got got lost and ran out of time. I noticed that on the downhill run that there is a lot of water coming out of the drain cocks. Is water used to help with braking when going down?
 

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The cylinders are used for compression on
the way down. Water is admitted to help keep them cool. The friction brakes are only used for stopping.
 

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Discussion Starter #10
You may have noticed that there is only one eccentric and no reversing mechanism as it coasted all of the way down. Our version will have reverse as weight does not scale down and we need reverse.
Roger's layout will vary between 2 and 10.5 degrees
 

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For the trip down the railway, the brake man is stationed in the coach and is actively using the brake to control the decent of the locomotive and coach.

Steve
 

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The locomotive and coach are braked entirely independently of each other. There is no coupling between the two, only a roller on the locomotive that pushes against a bumper block on the coach.

The locomotive sets the pace and uses the compression of the cylinders to control the speed. As Steve said, the coach is braked by the brakeman on board, using friction brakes. The modern coaches have a foot peddle for the brakeman that lets him feel how hard the coach is pushing on the locomotive. The idea is to have the two barely touching, except on some flatter areas where a little push from the coach is helpful to maintain speed. It's not uncommon for the coach to be separated from the locomotive by a few inches as grades and speeds change.

Roger
 

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Train-Li Cog holders

Look for the Train-Li cog railway holders. They should work great for your application because they slip onto the LGB rack rail but then screw into each tie with two screws so it doesn't matter the gauge of the rails. They are a lot harder to use because you need to put two screws in for each holder and, as always, a holder about every six inches on straights. But on curves where you may be placing a holder every 2-3 inches, it becomes a lot more work than popping in the LGB rack holders. On the other hand, the Train Li holders look more realistic. I bought a bunch of them on ebay one time when someone probably got rid of them after learning how much easier LGB are!

Here's the link to what you need:

https://www.trainli.com/cog-rail-62/tr15-082-p-73

Nice work!

Mike
 

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Bill, I see a 3D printer in your future.
 

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Discussion Starter #16
Mike
Do the holders slip into the groove in the rack on the male end or is there some cutting that needs to be done.
Dan
My Friend Dennis has one and I use Shapeways for SS and high res plastic pieces
 

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Bill
In Steam in the Garden issue # 151, Sept/Oct 2017, Mrk Horovitz converts a Accucraft Dora to a
cog RailwayLocomotive Check it out
 

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Discussion Starter #18
Thanks Noel
I speak with Mark on a regular basis. I'll reread the article and pick his brain on our next conversation.
 

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Train-Li Cog holders

Dan,

The Train Li Cog holders slip right onto the end of the rack rails with no cuts and then you can slide as many as will fit where you need to in order to screw them into the ties. The link at Train-Li shows them on the rack rail https://www.trainli.com/cog-rail-62/tr15-082-p-73 though that piece of rack rail has been cut which is not necessary.


Of course, once you add another rack rail onto the end, you've blocked egress for the holders unless you disconnect the rack rails. That's one of the difficulties about them. With the LGB holders, you can simply lift off the whole line of rack rail from the holders without having to separate individual lengths of rack rail. To do the same with the Train-Li holders, you'd have to unscrew them all first. So, I'd only put them in if you know exactly the track configuration you want OR if you're using a wider gauge as suggested here because they attach to the ties between the rails, not to the rails themselves.

By the way, they come with a couple little yellow plastic gauges that temporarily clip between the g-scale rails to assure proper alignment while you're screwing them in. Using six of these at a time holds the track in place as you are moving along installing them.
For a wider gauge, you'd have to eye ball it or create your own out of plastic or wood just to hold it in while your screwing it down.

The three pix show how they sit on the rack rails, how they slip on, and the gauge holders that come with them.

Hope this helps

Mike
 

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Mike, this is good information, thanks. These may be just the answer to what we were looking for.

I am having plywood centering jigs made per Bill’s design.

Roger
 
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