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partial turntable....

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Posted by GerryD on Friday, June 19, 2020 5:47 PM

Kevin, please read the theory of operation I posted earlier on. (9 steps) And then please read the proposed history.

The operation explains the “run around” and the direction change for the engine.

It IS a strange concept, you may just not yet see the possibilities.

This is "more" than running trains in a circle. Some people like very long trains and just watching them run. A club, local to me, is like that, I didn't join. Some others will jam as much track in an area as possible. Not really my thing. Others like an operation more like a real railroad with switching, and track arrangements that depend on a hypothetical history of the railroad and constraints on scenery, mountains and rivers, maybe even car floats. Some like interchange and then there are fans of John Allen's switching nightmare.

I have an area in a basement that is about 12 feet by 12 feet. It necessitates I have an around the room layout. I will have to have a little bit of it into the next area to accommodate a loop of mainline track to hidden storage area and on the other side a loop under some stairs. In this overall space I will have to make a layout that seems to operate over several miles. This partial turntable will make the operating sessions more interesting and the distance seem greater.

I will have a WORKING cable incline to a logging area. Yes Working, I had built it up, switch tracks at top and bottom, uncoupling ramps all as an experiment and it worked just fine.  

Turntables can be cantankerous, like you say, everything can be, that's part of the joy of things, making them work reliably.

I did take one thing away from your contradictory post, I will have  a buffer on the turntable track to prevent runoff the "open end". LOL, Thanks for that idea!

Cordially,

Gerry

http://kitbash.ourpage.org

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Posted by Anonymous on Friday, June 19, 2020 6:29 PM

GerryD
The whole idea of this was inspired by that Silverton turntable at Corkscrew Gulch at the end of a switchback. There the problem was they did not like to extensively back the locomotives. Either because there were no wheels under the cab to help guide the locomotives or because of a steaming issue.

The Silverton Railroad turntable at Corkscrew Gultch was a full length turntable.  The primary reason for the turtable was that the locomotive needed to be on the downgrade side of the train for safety when working some of the mines in the area.   As you suggested, the other reason is that the 2-8-0s did not track well in reverse, especially in the snow.  

GerryD
In modeling this would be hell on earth to make work.

  I'm going to do it.  Shouldn't be that hard, the track just needs to have just enough grade for the cars to roll clear of the switch from either leg.  The hardest part will be the scratchbuilt 50 ft turntable.

GerryD
So, the REAL question is, is this good enough to add to an operating session. Has anyone ever seen or heard of this except for on the Corkscrew Gulch?

  This was so rare that the American Society of Civil Engineers in Vol XXIIL No. 450 dated September 1890, published an article and drawing on this very topic.  

I have not heard of another use case similar to the SRR, nor one like you describe.

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Posted by Overmod on Friday, June 19, 2020 6:51 PM

Another thing the asymmetrical table offers is the ability to handle considerably longer power in a given 'width'.  With a different pattern of approach tracks this might be an interesting solution for a facility like CNJ's at Mauch Chunk (before there was a Jim Thorpe) where space between cliff and river was insufficient even for radial stalls and the 'roundhouse' consisted of a ladder track with parallel stalls skewed at an angle to fit required length.  This might be worked with even large power if only the 'table' had to be fit, perhaps with the 'minor diameter' actually near or in the river.

you would need separate ring rails adjacent to the pivot and on both 'radii' as the table won't balance and if rigid will have to swing on rails, only constrained laterally by the pivot pin.  The same inner ring rail would 'do' for both inner 'ends' of an articulated bridge (with wheels aligned as for heavy swing bridges, perhaps) and it seems likely to me that an air or electric motor assist would be useful.

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Posted by SeeYou190 on Friday, June 19, 2020 8:51 PM

rrinker
Kevin - not sure what you mean, both his sketch and the one pictured from Germany turn slightly MORE than 180 degrees.

Sorry for being unclear, what I meant was turning 180 degrees and going back the way you came onto the turntable.

The whole undertaking to me seems like a solution to a problem that does not exist. If the OP can get it working and enjoys it... than it is a great idea.

I will just stick to my old reliable Bowser turntables.

-Kevin

Living the dream and happily modeling my STRATTON AND GILLETTE Railroad in HO scale. The SGRR is a freelanced Class A railroad as it would have appeared on Tuesday, August 3rd, 1954, in my personal fantasy world of plausible nonsense.

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Posted by GerryD on Thursday, July 21, 2022 10:12 AM

Ben a heck of a few years.

I lost my wife almost two years ago, not from COVID but the stress of it played a part in a heart attack. She died in my arms so to speak while I was administering CPR, ambulance came and they were just about useless.

But back to the turntable, everything was delayed and I'll be getting back to work on things. A picture of what I want to make is here: DRG Class 41 on Neuenmarkt turntable - Railway turntable — Wikipedia

and: https://www.google.com/maps/place/95339+Neuenmarkt,+Germany/@50.0937597,11.5814329,169m/data=!3m1!1e3!4m5!3m4!1s0x47a19fc2851fb883:0x41db728f061e380!8m2!3d50.09418!4d11.5837281

Cordially, Gerry

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Posted by snjroy on Thursday, July 21, 2022 10:48 AM

I'm sorry for your loss Gerry.

The turntable is quite interesting - a way to save space in a tight environment, from what I can see. Anything is dooable I guess. You will need two sets of half-rings to support the table. Were you thinking of kitbashing an existing turntable or making one from scratch? I would not dare a such complicated project, but if I was forced to, I would go for the latter. I've read that some folks have used an audio plug (male and female) for the main axle of the table. 

EDIT - here is one example: 

https://www.delmarvamodelrailroadclub.org/NeatStuff/TunTable/Turntable.html

 

Simon

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Posted by AEP528 on Thursday, July 21, 2022 10:56 AM

The partial turntable doesn't save space if the intent is only to turn a locomotive 180 degrees. It requires a tail track, run-around track, and two turnouts that a full turntable doesn't need.

The full diameter of the turntable would simply take up the space needed by the run-around track. No real railroad would build more, or something more complicated, than needed without good reason. Probably the roundhouse and turntable in Germany were built that way because additional property was simply not available.

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Posted by doctorwayne on Thursday, July 21, 2022 11:51 AM

After reading through the earlier portion of this thread (with some missing photos and links), I fail to see any need for most of the discussion.
You have a locomotive that needs to be turned, but don't have room for a complete turntable. 
While the German version, shown in one of the still remaining photos, was, I guess, quite an innovation, I think there's way too much angst over what you want to do.
Instead of all this hemming and hawing, simply replace your locomotive with a smaller one, which will fit onto a smaller turntable that's completely round (and easy-to-build).

Wayne

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Posted by Colorado Ray on Thursday, July 21, 2022 6:42 PM

SeeYou190

From what I see, these "Partial Turntables" Cannot turn a locomotive 180 degrees, and require an extra approach track as a run-around.

 

-Kevin

 

Kevin is correct.  This "turntable" is a prototype sector plate that's only useful for getting the locomotives into the shed.

If Gerry's turntable location is near the edge of his benchwork, then model only enough of a turntable pit to reach the center pivot.  When the table turns, the end can swing out into the aisle.  This allows for the full 180 (or 360 if you want a merry-go-round) rotation to turn the engine.  This makes use of the aisle space similiar to folks that have drop down wyes in their aisles.  I was watching a YouTube the other night that included this feature.

 

Ray

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Posted by GerryD on Thursday, July 28, 2022 4:44 PM

 

Well it's a novel thing. It might fit the scheme of the layout and timeline. (Or so I think) The idea is that the turntable would be between a drop off with a mainline below and a rock cliff on the other. I'm thinking along the lines of a tourist line evolved from a branch line. Or a nearly abandoned line. Think Strasburg Rail Road in Pennsylvania. It was almost abandoned and then a group bought it and developed it from a little four when diesel to a major tourist rail road.

 

The idea I'm going for is that when the acquired steam engines, (MDC 2-8-0s) were in front of the passenger cars and going forward, all was well, but then when backing up trailing the passenger cars or backing up leading the passenger cars, derailments happened. So taking the idea from the Germans, they constructed this half turntable in the limited space at the end of the switchback and runaround track.

 

I thought of that idea long ago about the 1/4” audio jack, just never did anything with it. Thanks for reminding me though.

 

What I'll probably do is use a servo. Worst case, a manual turntable or a hand crank.

 

I look for things a little different.

 

Case in point the models I designed way back for MDC's Kitbash series.

 

( kitbash.ourpage.org )

 

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Posted by Colorado Ray on Thursday, July 28, 2022 8:48 PM

Gerry, I still don't understand what you are trying to do.  The half turntable will NOT allow you to turn the engine around.  At the end of the line the engine will still have to backup to go home.  

Ray

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Posted by gregc on Friday, July 29, 2022 4:36 AM

Colorado Ray
The half turntable will NOT allow you to turn the engine around.

isn't it just a way to get a loco onto the roundhouse tracks, not turn the engine?

greg - Philadelphia & Reading / Reading

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Posted by SeeYou190 on Friday, July 29, 2022 9:04 AM

gregc
isn't it just a way to get a loco onto the roundhouse tracks, not turn the engine?

The example in Germany can turn the engine around, but onto an approach track on the other side of the turntable. Then the engine must be run back to the line.

It requires a lot more movement.

-Kevin

Living the dream and happily modeling my STRATTON AND GILLETTE Railroad in HO scale. The SGRR is a freelanced Class A railroad as it would have appeared on Tuesday, August 3rd, 1954, in my personal fantasy world of plausible nonsense.

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Posted by doctorwayne on Friday, July 29, 2022 11:08 AM

GerryD
...The idea I'm going for is that when the acquired steam engines, (MDC 2-8-0s) were in front of the passenger cars and going forward, all was well, but then when backing up trailing the passenger cars or backing up leading the passenger cars, derailments happened.

I no longer have my MDC Consolidation, but it's wheelbase is pretty close to that of my Bachmann Consolidations which is 65' (HO) or about 9".
If you can't find room for a 9" turntable, you need to revise your trackplan. 

I was going to add a turntable and three stall roundhouse to my layout, but discovered that the two would not fit into the spot I had chosen. 
In order to accommodate both, I took the roundhouse apart, changing it into a "squarehouse" (sorta), then scratchbuilt a turntable that would fit.   (I had a Walthers 90' turntable on-hand, but there was not quite enough room for it).

The turntable that I built was a block of wood, with  cut-up Atlas through-girder bridges cut apart and cemented to the sides of the wood.  The turntable is finger-powered, and rotates on the cut-down beater-shaft of a food mixer. 
My 87' (HO) turntable will handle all of my steam locos.

Some pictures...

...and what became of the former roundhouse...

I'll add more photos when photobucket gets its act together.

Wayne

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Posted by Colorado Ray on Friday, July 29, 2022 10:14 PM

gregc

 

 
Colorado Ray
The half turntable will NOT allow you to turn the engine around.

 

isn't it just a way to get a loco onto the roundhouse tracks, not turn the engine?

 

Exactly, which is what I had said in my earlier post.   It's like a giant sector plate.  By itself it can't turn an engine around.  I don't follow what Kevin says either.  Just going through an engine house doesn't change direction unless the other side of the engine house completed a wye.  If that's the case, the "turntable" functions as nothing more than a very very low number turnout.

 

Ray

 

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Posted by John-NYBW on Saturday, July 30, 2022 8:52 AM

I'm joining this discussion fairly late so the points I am going to make might already have been covered. The turntable shown in the OP is designed only to move the locos into the half roundhouse. It cannot turn a loco. For that, the bridge would have to pivot on the center so the loco can exit the bridge facing the opposite direction that it entered. 

I'm debating whether to use a half pit turntable at the end of my branchline. I've seen a few examples of such turntables and they are built into a slope. The pit wall only goes a little more than halfway around but the floor of the pit has to be 360 degrees in order to allow the bridge to rotate 180 because both ends of the bridge must be supported at all times. Such a TT does not save space because its diameter must be the the length of the bridge. The TT will serve a two stall engine house and there will be no garden tracks. If I do this, it will be for visual interest only, not to save space. 

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Posted by SeeYou190 on Saturday, July 30, 2022 8:57 AM

Colorado Ray
 I don't follow what Kevin says either.

This is a simplified sketch of how the one in Germany is used.

-Kevin

Living the dream and happily modeling my STRATTON AND GILLETTE Railroad in HO scale. The SGRR is a freelanced Class A railroad as it would have appeared on Tuesday, August 3rd, 1954, in my personal fantasy world of plausible nonsense.

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Posted by John-NYBW on Saturday, July 30, 2022 10:31 AM

SeeYou190

 

 
Colorado Ray
 I don't follow what Kevin says either.

 

This is a simplified sketch of how the one in Germany is used.

-Kevin

 

OK, I stand corrected. I didn't notice from the original picture that there was an exit track on both ends. That would allow turning a loco that is going to an adjacent track. 

I hadn't seen that kind of arrangement before and it is interesting. It gives me another option and I can see the space savings which in my situation would be very beneficial. I had thought of a TT with a wall only part way around the pit but would have required a full pit. This would allow a pit a little over half the diameter of the pit. Back to the drawing board. 

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Posted by SeeYou190 on Saturday, July 30, 2022 1:24 PM

John-NYBW
I didn't notice from the original picture that there was an exit track on both ends.

.

There was a track plan posted on page one, but it has disappeared.

I am glad my sketch made sense. Hopefully GerryD will correct anything I got wrong.

-Kevin

Living the dream and happily modeling my STRATTON AND GILLETTE Railroad in HO scale. The SGRR is a freelanced Class A railroad as it would have appeared on Tuesday, August 3rd, 1954, in my personal fantasy world of plausible nonsense.

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Posted by Colorado Ray on Saturday, July 30, 2022 9:05 PM

SeeYou190

 

 
Colorado Ray
 I don't follow what Kevin says either.

 

This is a simplified sketch of how the one in Germany is used.

-Kevin

 

Thanks Kevin.  Very good explanation.  In essence the turntable functions as a leg of a wye, and does indeed allow for turning the engine In a much reduced space.

Ray

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Posted by doctorwayne on Saturday, July 30, 2022 10:04 PM

Well, Kevin's drawing is a nicely-done way of showing how the loco is turned (I was having trouble trying to understand the set-up through the written descriptions), but I can't at all agree that it's in a much reduced space....you've got two turnouts and two tracks to accomplish a simple turn-around that could be done with a single turnout and a much shorter single track.  Size the turntable to match your locomotive's wheelbase (not to it's over-all length) and I'd guess it would take less room than the one explained in Kevin's drawings.

Wayne

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Posted by gregc on Sunday, July 31, 2022 6:14 AM

doctorwayne
but I can't at all agree that it's in a much reduced space.

more that it fits in the space available

unlike america, where towns often grew around railroads, the RRs of Europe needed to find space within existing cities.

my understanding is there is no central RR station in Paris, there are separate lines that partially enter Paris with separate stations

greg - Philadelphia & Reading / Reading

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Posted by John-NYBW on Sunday, July 31, 2022 7:15 AM

doctorwayne

Well, Kevin's drawing is a nicely-done way of showing how the loco is turned (I was having trouble trying to understand the set-up through the written descriptions), but I can't at all agree that it's in a much reduced space....you've got two turnouts and two tracks to accomplish a simple turn-around that could be done with a single turnout and a much shorter single track.  Size the turntable to match your locomotive's wheelbase (not to it's over-all length) and I'd guess it would take less room than the one explained in Kevin's drawings.

Wayne

 

I began fiddling with this idea as a possible solution for the turntable at the end of my branchline but realized that it requires more length but saves nothing width wise.  Whether using this arrangement or a conventional turntable, the bridge has to be at least as long as the longest piece of equipment. In a conventional turntable, the pit diameter is the same as the bridge. In this half moon pit, the diameter is actually going to be greater than the length of the bridge. In my case, I can get by with a 7 inch (HO) turntable but if I used the proposed TT, my pit would need to be longer. The pit floor still has to be 7 inches wide although it doesn't require the full circle on the one half. 

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