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Live Steam Cog Loco Build

14K views 52 replies 24 participants last post by  HMeinhold 
#1 · (Edited)
Guys,
I have not posted here for a very long time for different reasons. Currently I am working on a new project, a cog loco in 1:22.5. I chose this scale as I plan to return to Germany in a couple of years. The loco is a model of the first combined rack/adhesion narrow gauge engine built by a Swiss company. It was an industrial switcher and did not have the tilted cab as other rack locos. So I can run it on ordinary track and then branch out to the rack-equipped line. Most of the readers here are not very interested in builds if they are not American prototypes or BIG. So I am reluctant to post it here, though it is technically very challenging. It is small, with an unusual Gooch valve gear (designed using the Dockstader program and Alibre simulation) between the frames and the kinked side rods to get the cog wheel to clear the rails on switches. It was also pretty difficult to design a gear, which meshes with the LGB rack and also a pinion for speed reduction. Another challenge was to match the cog pitch diameter with the diameter of the driving wheels. A complete build thread is here (in German, but with lots of pictures) http://www.buntbahn.de/modellbau/viewtopic.php?t=13117
A set of drawings was found in an old brochure: https://books.google.com/books?id=q...v=onepage&q=zahnradlok wasseralfingen&f=false
The drawings are towards the end, so scroll down.
Currently the chassis runs on air, the boiler and burner/gas tank are finished and I am working on the boiler fittings/piping. If you guys are at all interested, I will post some of the progress here. So here is a picture:




Regards
 
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#4 · (Edited)
I designed the wheels in Alibre and then Dennis cut them on his CNC mill. The material is precision ground flat steel. By the way, I helped Dennis with the soft/hardware in modifying his mill, which took some time - one of the reasons for not posting here. Since then we (Bill Allen and me) are regulars in his workshop and extremely grateful for his help. Here is a view of the crammed chassis with the Gooch valve gear. Most joints have tiny ball bearings (about 0.04"(1mm) ID and about 1/8" (3mm)OD), to minimize lost motion.
Regards

.
 
#6 ·
Been following your post on the "Buntbahn forum" ,i am impressed with your quality build loco! Bill,Henner and a couple more master builders always catch my attention ,its a "must read" issue!!!
Thanks for posting,
Manfred
 
#11 ·
GUYS

If you haven't gone to the Buntbahn link in the top posting, You should do that when you have a little time to examine the pure craftsmanship by Henner and Dennis.
I have been lucky enough to have seen the build from the start with the inventive ways they have approached every step. It is in German, but at least on my computer, there is a translation block the the top.
 
#14 ·
@Bill,
thanks for the kind words. In fact, we are both part of a Saturday workshop. This informal get-together is a valuable source of information and knowledge exchange.
@David,
this is the rack I use:
https://www.onlytrains.com/model/tr...NuPPCHXn9Gn5t7BC_SUvQillZDXhh-khoCIz0QAvD_BwE
It seems to be quite durable (glass fiber reinforced?) and clips to any LGB track and even can be curved (R3 at least). Unfortunately the pitch is not to any standard, so we designed our own gears. Dennis had a program which allowed us to manipulate all the parameters of a gear. We then cut these with the laser out of acrylic and checked how they meshed.

Regards
 
#20 ·
In an early post, you said Swiss adhesion/rack engine. Does that mean this engine is capable of running on non-rack sections in between rack rail sections?
Ive been to Mt. Washington Cog RR and Pikes Peak Cog RR, and they both have racks installed on every inch of track.
I was wondering how the engine proceeded from non-rack rail onto the rack rail and get the gear in alignment with the rack?
 
#22 · (Edited)
In an early post, you said Swiss adhesion/rack engine. Does that mean this engine is capable of running on non-rack sections in between rack rail sections?
Ive been to Mt. Washington Cog RR and Pikes Peak Cog RR, and they both have racks installed on every inch of track.
I was wondering how the engine proceeded from non-rack rail onto the rack rail and get the gear in alignment with the rack?
They had (and still have today) a very sophisticated system to synchronize the gears when entering the rack section. First a hinged section at the beginning of the rack was set on springs in case the gear happened to sit on top of a tooth. Secondly the pitch of this section was slightly different from the pitch of the gear. This ensures that after a couple of feet the gear synchronized with the rack. Also sometimes the height of the teeth varies. Many Swiss rack systems today switch between adhesion and rack at fairly high speed using this method. See e.g. https://www.google.de/search?q=zahnstangeneinfahrt&source=lnms&tbm=isch&sa=X&ved=0ahUKEwih8KOGxc7gAhUPVK0KHVb3CR4Q_AUIDigB&biw=1536&bih=701&dpr=1.25.
The prototype of my loco ran without rack within the iron works and entered the rack section when climbing up a hill.
Regards
 
#23 ·
The boiler fittings (manifold/throttle/safety valve/dead-leg lubricator/water gauge) are done. It was pointed out to me (I should have known better), that the water gauge should not be tapped off the manifold, as opening the throttle will affect the reading. I will proceed with the remaining plumbing and then test the loco under steam. If the gauge really misreads, I will solder a separate bushing into the boiler. Yesterday we milled the reach rod out of 1/16" steel. Here how the loco looks like now:



The throttle handle is some black rosewood, donated by Dennis.
Regards
 
#25 ·
I saw a Ruby with a sight glass fitted like yours. It would not run at all due to water being drawn off the bottom of the boiler through the sight glass and through the throttle valve. The cylinders would never clear.
Good luck, beautiful build so far.
Keep 'em Steamin'
John
 
#27 · (Edited)
Eric,
the throttle was a bit of a headache. In the real loco it is housed in the dome. I could not do that, as there is absolutely no space on the front end for a lubricator. So I put the throttle into the manifold, having to use a fairly long steam line (the Ruby has about the same length, so I might be OK). Here is a picture of the throttle proper (the M4 thread is not shown):





and the temporary routing of the steam lines:




Regards
 
#28 ·
Very interesting project Henner...thank you for sharing your progress.

A small suggestion...you may want to consider insulating the steam line running from the manifold forward to the split "T" over the front of the boiler...The plastic tubing you have used would be an excellent insulator...even if you need to split it to get it to fit.

Alternatively if you can do a few bends and run the steam line from the manifold through the firetube you can do a great job of keeping the steam hot and avoid condensation....I hesitate to call it a superheater line, but it would act somewhat as one.

Otherwise, with no insulation you'll have a lot of heat loss in that copper tube between the manifold and the front.
 
#29 ·
Cliff,
In the Ruby the steam line runs from the throttle via two bends through the lubricator and then uninsulated under the boiler to the fairly bulky reverser valve with a lot of surface. The line is longer and has more surface area than my pipe system. The Ruby design seems to work OK. Obviously the heat transfer between the fast moving steam and the wall of the pipe is not outrageously high. But I will definitely insulate the long pipe, as the prototype tube had a fairly large diameter. However I will first test the temporary piping to see, what happens.
Regards
 
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