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Turntable to turn the entire train!

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Posted by CSX Robert on Friday, October 17, 2008 10:34 AM
scottychaos
...interesting idea..wouldnt quite work in my case though, because it blocks the door...
Oops, forgot about that door! If you have the turntable always return to the position on the right, you could have the longer approach track removeable or hinged on the left so that you can lift it up out of the way and have a clear path through the doorway.
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Posted by scottychaos on Friday, October 17, 2008 6:33 AM

Wow!

very good ideas all around!

thanks everyone!

I like the idea of the two overlapping reverse loops..both taking up the same space.. that could work! :) thanks for the idea..

CSX Robert

Here is something you might want to consider.  Instead of having a normal turntable, have it pivot around to where the turntable track is parallel to the approach track and have it line up with a spur off of the approach track.  The advantage with this arangment is that it only protudes into the room a few inches except when it is actually rotating, so you do not have to move anything out of the way when you are not operating.  I replaced one of the turntables in your drawing with what I am trying to describe here: 

http://www.trainboard.com/railimages/uploads/7570/6-foot-turntables.jpg

 

 

thats different! interesting idea..wouldnt quite work in my case though, because it blocks the door..but I could maybe fit it in somewhere else..definately something to keep in mind!

based on all these great ideas, im working up a few new drawings..I will post some more of them soon..

thanks,

Scot

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Posted by doneldon on Friday, October 17, 2008 1:27 AM

Yet another idea: Run the trains all of the way around the room to a 5' run through turntable.  This would permit continuous running around and around, or loop-to-loop (actually Ttable-to-Ttable) while requiring that you construct only one turntable.

 

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Posted by doneldon on Friday, October 17, 2008 1:12 AM

Another idea: I know you don't like around the walls but you could go around the walls between two reverse loops, stacked on top of one another (loop-to-loop).  You woudn't need a lot of grade separation and it would allow you to save a bunch of real estate.  The total usage would be less than a 5' turntable at each end, unless you stack these, too.  However, you might need considerably more grade separation for access to the lower turntable.

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Posted by doneldon on Friday, October 17, 2008 1:03 AM

This would still require a 5' semicircle, not to mention space for the operator.

 

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Posted by bladeslinger on Thursday, October 16, 2008 9:27 PM

real railroads do not generally turn entire trains, with few exceptions.  and they don't use turntables to turn them when they do.  a wye would make a lot more sense, and create many more operating possibilities.  but why do you want the entire train turned?  why not cut the train off on the mainline, then take the engine(s) around a wye or to a turntable to be turned, then have the engines run around the cars in a passing siding to get to the other end.  this is far more prototypical, and actually very common in both past and present railroading. 

real railroads sometimes turn cars to meet the requirements of a customer, such as a boxcar that has to be unloaded from a certain side, or turning auto racks so they can be unloaded from the end the customer desires due to them having their ramps on a certain end of their facility.  and in some cases a short local might actually turn the entire train using a wye, but most of the time it'd just be a few cars.

 

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Posted by Alan Robinson on Thursday, October 16, 2008 7:48 PM

Scot, I've read most of the other posts, including the last one showing the "turntable" that is really a long arm that folds back along the approach track and connects to a spur off the approach track. I thought about this idea before I got to that post and I liked it, too. One other variation to consider would be to make the "turntable" a section of curved track as there is nothing that requires it to be straight. this might fit into your track plan better than a straight one. This would allow you to curl the whole thing into a corner.

It wouldn't be too difficult to automate that kind of operation. If your locomotives and cars have all metal wheels it is pretty easy to use those as sensors to indicate when the locomotive gets to the end of the turntable. Moving the turntable slowly and smoothly isn't too difficult, either. You would have to be willing to put together the hardware yourself but you could do it using mostly off the shelf stuff. That's a lot easier and usually less expensive than constructing your own from scratch.

If, you're interested, let me know by e-mail and I would enjoy kicking around some ideas in a more substantial manner than is possible in this forum.

By the way, I really liked the modelling work on the Sandy River coach you built.

Alan

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Posted by el-capitan on Thursday, October 16, 2008 4:08 PM

CSX Robert

Here is something you might want to consider.  Instead of having a normal turntable, have it pivot around to where the turntable track is parallel to the approach track and have it line up with a spur off of the approach track.  The advantage with this arangment is that it only protudes into the room a few inches except when it is actually rotating, so you do not have to move anything out of the way when you are not operating.  I replaced one of the turntables in your drawing with what I am trying to describe here: 

Robert, great design. I like it.

 

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Posted by CSX Robert on Wednesday, October 15, 2008 8:01 PM

Here is something you might want to consider.  Instead of having a normal turntable, have it pivot around to where the turntable track is parallel to the approach track and have it line up with a spur off of the approach track.  The advantage with this arangment is that it only protudes into the room a few inches except when it is actually rotating, so you do not have to move anything out of the way when you are not operating.  I replaced one of the turntables in your drawing with what I am trying to describe here: 

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Posted by CSX Robert on Tuesday, October 14, 2008 9:17 PM
 dehusman wrote:
...
The hard point is slowing down the train on the turntable and acceleratign it off. With DC is fairly simple to vary the track voltage. With DCC you have to have something communicating with the command station and it has to know which engine its controlling. It has to know that engine 17 is pulling on the turntable since its only going to control the decoder in engine 17. That will probably require some software and a computer interface.

The simple way to go is to just cut the power Have a sensor that detects when the engine reaches the end of turntable and it just activates a relay, electronic or mechanical, that cuts the power to the turntable. The train just stops (depending on how much momentum any flywheel contributes). After the turntable rotates it trips another relay, that turns the power back on. The downside is the lurching to a stop and a start. Visually it won't be a problem since it will be off scene, the only concern would be mechanical. 

Dave H.


There are two ways to stop and start the train wihtout just cutting the power and without having to know the address of the engine. Set the decoder to "Brake on DC" if it supports it, and if you switch the turntable power to DC, the train will slow to a stop using the deceleration value programmed into it. The other option is to use a DCC brake district. You would have to have a method for generating a broadcast "set speed zero" packet(the programming outputs of a DCS100 can be configured to do this or you can get a "Set Speed Zero Packet Generator" from DCC BitSwitch:http://www.dccbitswitch.com/) and a seperate booster for the brake district. This method is more expensive, but has the advantage of working with decoders that do not support "Brake on DC". I believe that you could also use the MRC BlackBox to create a braking district, because I think it outputs DCC commands using the broadcast address, although I have not confirmed this.
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Posted by scottychaos on Tuesday, October 14, 2008 8:30 PM
 superbe wrote:

Just out of curiosity, are these "extra long" cars and locomotives actually available????. If so I must have missed them in the catalogs and web sites.

Bob

 

Not really available commercially, no...well, not through the normal hobby catalogs anyway.

Most On2 models up to recent times have only been available in wood "craftsman kit" form, or brass..

no plastic "ready to run" at all..

there is still no plastic R-T-R, although with the recent introduction of the Bachmann On30 forney, based on Maine 2-foot prototypes, the interest in Maine 2-footers is beginning to grow a bit..in both On30 and On2..(some model the Maine 2-footers in On30, which the track gauge being 6" too wide..just as many people model Colorado 3-foot gauge in On30, with the track gauge 6" too narrow..just because On30 is easy and available.)

There are now some laser-cut kits beginning to come out for maine prototypes though, passenger and freight cars..so more is becomming available..slowly.

As for length, here is a scale-length Maine coach I built from two Bachmann On30 coaches:

 

and a webpage with more detail on the build:

http://gold.mylargescale.com/Scottychaos/On2/index.html 

 

The prototype Maine car was nearly 50 feet long (49' to be exact) while the Bachmann On30 coach scales out to only 36 feet long..Maine rolling stock is generally longer and narrower than most available On30 rolling stock..

And here are more thoughts on On2 vs. On30..if anyone is interested:

http://gold.mylargescale.com/Scottychaos/On2-SRRL9/index.html 

Scot 

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Posted by dehusman on Tuesday, October 14, 2008 6:08 PM

 wjstix wrote:
One thing though...if you're going to build the layout with the two "full train" turntables, do you really need two regular turntables with roundhouses (and what appears to be an engine house)??

This created an idea.  if you put the turntable near the corner of the layout room, you could use the same turntable for either end and when you turn the turntable it could "open up" the aisle for entry.  Simplified idea, draw a loop and put a turntable in the loop,  When you rotate the turntable 90 degrees you open up at least a 2 ft "aisle" in the loop.  So by positioning it correctly you could have a continuous loop or a turntable at each "end" of a point to point layout, plus unrestricted access into the layout.

Dave H.

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Posted by Midnight Railroader on Tuesday, October 14, 2008 5:42 PM
 superbe wrote:

Just out of curiosity, are these "extra long" cars and locomotives actually available????. If so I must have missed them in the catalogs and web sites.

Bob

What, you didn't see the On2 86' autoracks and Superliners?
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Posted by superbe on Tuesday, October 14, 2008 4:35 PM

Just out of curiosity, are these "extra long" cars and locomotives actually available????. If so I must have missed them in the catalogs and web sites.

Bob

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Posted by el-capitan on Tuesday, October 14, 2008 4:16 PM
 wjstix wrote:
 dehusman wrote:

 scottychaos wrote:
I agree the sudden jerky starts and stops arent that great though..

In reality, even if you did ramp down the speed, it would still have to be fairly quick, so there may not be that much difference between a ramp down over a distance of 6 inches and a straight shut off.  On the other hand, a ramp up could be longer and less jolting.

Dave H.

If the turntables are out of sight, it wouldn't really matter if the stops were kinda sudden, unless the speed/stop was so violent it caused a derailment.

 Sudden starts and stops put alot of uneeded stress on the drives of your locos. Depending on how much you plan on running the trains, it could be a problem.

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Posted by wjstix on Tuesday, October 14, 2008 3:43 PM
 dehusman wrote:

 scottychaos wrote:
I agree the sudden jerky starts and stops arent that great though..

In reality, even if you did ramp down the speed, it would still have to be fairly quick, so there may not be that much difference between a ramp down over a distance of 6 inches and a straight shut off.  On the other hand, a ramp up could be longer and less jolting.

Dave H.

If the turntables are out of sight, it wouldn't really matter if the stops were kinda sudden, unless the speed/stop was so violent it caused a derailment. The starts wouldn't be a problem, since when power is reapplied the CV3 momentum settings could be set to gradually bring the engine up to full speed.

Actually DCC would make great sense in a small layout, not have to worry about blocks if you do want to run two engines at the same time.

One thing though...if you're going to build the layout with the two "full train" turntables, do you really need two regular turntables with roundhouses (and what appears to be an engine house)?? If you're going to have 10+ locomotives I guess you might, but otherwise removing one TT/RH would open up space for something else.

Stix
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Posted by dehusman on Tuesday, October 14, 2008 1:51 PM

 scottychaos wrote:
I agree the sudden jerky starts and stops arent that great though..

In reality, even if you did ramp down the speed, it would still have to be fairly quick, so there may not be that much difference between a ramp down over a distance of 6 inches and a straight shut off.  On the other hand, a ramp up could be longer and less jolting.

Dave H.

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Posted by dehusman on Tuesday, October 14, 2008 1:48 PM

 el-capitan wrote:
However, it brings up a whole different question, if you are just planning on 1 train operation, do you really need DCC?

Three word answer:

Sound, special effects.

Plus he may have another train switching in the yard.

Dave H.

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Posted by scottychaos on Tuesday, October 14, 2008 1:20 PM
 el-capitan wrote:
 dehusman wrote:

The simple way to go is to just cut the power  

I admit I know nothing about DCC but doesn't cutting the power cause problems when the power is turned back on?

However, it brings up a whole different question, if you are just planning on 1 train operation, do you really need DCC? I guess I don't remember if you stated if you are planning on DC or DCC.

 

No, I dont think cutting the power would hurt at all..in fact, it could be very useful!

Drive train onto bridge, cut power (somehow) to stop the train.

Turn the table 180 degrees.

Turn power back on..train starts back up right where it left off and heads off trhe table..

I agree the sudden jerky starts and stops arent that great though..

Im running DCC because I think it will be much easier than DC..and my first engine came with DCC sound..and IMO it is a far superior way than DC to run a railroad..even a small one.

so basically im using DCC "because I can"! ;)

Scot

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Posted by el-capitan on Tuesday, October 14, 2008 1:05 PM
 dehusman wrote:

The simple way to go is to just cut the power  

I admit I know nothing about DCC but doesn't cutting the power cause problems when the power is turned back on?

However, it brings up a whole different question, if you are just planning on 1 train operation, do you really need DCC? I guess I don't remember if you stated if you are planning on DC or DCC.

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Posted by dehusman on Tuesday, October 14, 2008 12:36 PM

 scottychaos wrote:
I know DCC technology exists that will automatically handle the polarity changes..thats a no-brainer..but as for the rest..I dont know..

The polarity changes don't even have to be DCC related, a pair of wipers on the turntable pivot or will change the polarity on the turntable itself, 1950's era technology.

The hard point is slowing down the train on the turntable and acceleratign it off.  With DC is fairly simple to vary the track voltage.  With DCC you have to have something communicating with the command station and it has to know which engine its controlling.  It has to know that engine 17 is pulling on the turntable since its only going to control the decoder in engine 17.  That will probably require some software and a computer interface.

The simple way to go is to just cut the power  Have a sensor that detects when the engine reaches the end of turntable and it just activates a relay, electronic or mechanical, that cuts the power to the turntable.  The train just stops (depending on how much momentum any flywheel contributes).  After the turntable rotates it trips another relay, that turns the power back on.  The downside is the lurching to a stop and a start.  Visually it won't be a problem since it will be off scene, the only concern would be mechanical. 

Dave H.

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Posted by dknelson on Tuesday, October 14, 2008 8:39 AM

The late Ben King had just the sort of "entire train turntable" for the staging portion of his small but perfect layout.  It can be done.  

An idea that has been knocking around my head for a while is a turntable without a pivot point.  At the far end of staging, the tracks end and a glossy smooth white writing board, of the sort seen on office walls to be used with dry erase markers, would continue.  The "turntable" would be a length of track mounted on a thin board, with felt at the bottom so it would travel smoothly on the white writing board.  This could be turned around like a turntable, or simply moved to other yard tracks in the manner of a cassette or sector plate such as many British layouts use. 

Electric connections, and perhaps also the mechanical linking up with the yard tracks, could be accomplished with a series of knife blade electrical contacts, of this sort:

 

 

with the knife blade axis on one part and the sleeve like holder on the other, one for each rail.  Something like this was shown in on or another of the magazines some years ago.

Dave Nelson

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Posted by ChrisNH on Tuesday, October 14, 2008 7:10 AM

Looking at your plan, it looks like it may be feasible to build a closed loop around that area outside the layout room. It would not need to be very big at all and could run through shelves, etc. Put a turntable in the middle (or one end..) of that. You would have the ability to run continous without automation. When you want to "operate" you would be able to run trains into a single turntable from either direction. If you were so inclined, you could also have multiple staging tracks. It would basically combine the features of US hidden staging with UK train turntables..

Chris

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Posted by R. T. POTEET on Tuesday, October 14, 2008 2:22 AM

This has been done on British layouts but I can't recall ever having seen it done on this side of the pond. Usually it was done with extremely short branchline passenger trains--a tank engine and two cars. In British O-Scale--7mm--five feet scales to a hair longer than 200 feet;in OO/HO-Scale--4mm--scales to almost 400 feet but I don't ever recall seeing this type of operation done in this latter mentioned scale.

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Posted by loathar on Monday, October 13, 2008 7:39 PM
 scottychaos wrote:
 dehusman wrote:

I guess I don't understand the advantage to turning the whole train as opposed to turning just the engines, its not like its going to run like a continuous loop anyway. 

If you are going to do the turntable make the table 12" wide and put 3 tracks on each one so you can stage 3 trains on each end and send them back out in a different order if you want.

Dave H.

 

because I would like this to be fairly automated..if possible..

So that when I am "operating the layout" in the train room, the train can run "off scene" to the reverse loop or turntable, and automatically return all by itself..while I never leave the train room.

 

I was thinking the same thing about automating it. That's a great idea and fairly EZ to do.

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Posted by el-capitan on Monday, October 13, 2008 4:37 PM
 scottychaos wrote:
 

I bet someone somewhere has done this already! Big Smile [:D]

just need to figure out how..

Scot 

 Yes, I have seen similar things done before, but never without significant knowledge, time and money. I'm not saying it's impossible. Just alot easier to put in a reverse loop.

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Posted by scottychaos on Monday, October 13, 2008 4:30 PM
 el-capitan wrote:
 scottychaos wrote:

I would also like the railroad to be able to operate continiously if I want..(one train only)..I dont want a true "point to point" railroad where the train always has to be stopped at both ends..I dont want *quite* that much operation! Wink [;)] I dont mind some operation..but im more of a "let the trains run and just watch them" kind of guy..detailed "operations" isnt really my thing.

 

 Unless you have substantial experience with robotics, programmable logic controllers and/or Computer integrated mechanical systems, I would stick with the reverse loops for continuous operation.

To have this fully automated you are asking for the following sequence of operations:

1. The train enters the turntable at normal speed and trips a sensor (sensor #1). This (somehow) tells the control system (PLC or computer) to begin slowing the train.

2. When the train reaches the end of the turntable, sensor #2 trips and tells the control system to shut off power to the train.

3. The control system checks that sensor #1 is unblocked (meaning the train has fully entered the turntable.) . If so the table is rotateda 1/2 rotation.

4. The control system checks that a third sensor is tripped which confirms that the tracks are indeed lined up.

5. At this point the train is accelerated back up to normal speed but with the polarity reveresed.

Keep in mind that you will need to do this twice, once for each end.

 Maybe somebody on here is more inventive than me but I don't see a way to accomplish this without alot of fancy electronics.

 

 

 

hmmmm..

good points, thanks..

I guess I was thinking this technology must already exist for normal turntables..but perhaps not..because with a normal turntable on a layout the operator has the locomotive in view, and manually stops it in the middle of the turntable bridge, just by sight...but that wouldnt work for the system im envisioning..

I know DCC technology exists that will automatically handle the polarity changes..thats a no-brainer..but as for the rest..I dont know..

this is why I ask! :)

I bet someone somewhere has done this already! Big Smile [:D]

just need to figure out how..

Scot 

 

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Posted by tinman1 on Monday, October 13, 2008 4:13 PM
I'm not sure about DCC, but you could do a standalone system in DC. A couple ball-locks to "key" the turntable, and two photo-optic sensors hooked up to relays to kill track power and energize the turntable motor. One located at either end of the turntable, with the farthest being the "operational" one. The one closest to the trackage could be set up to prevent rotation if it's not clear.  I would put some sort of bumper at the far end to prevent any "momentum" issues and ensure the center pivot is solid and up for the job. I would probably use a tapered roller bearing from a car, and some sort of light boxed metal (possibly 2 metal studs glued n screwed together) for the bridge. Anything short of rock solid will only provide a mild heart condition when you hear the thud in the other room right after the train went in.
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Posted by cacole on Monday, October 13, 2008 4:03 PM
Way, way, back when, Lionel made a turntable that was long enough to turn an entire Burlington Pioneer Zephyr 3-car train.  I think it was turned with a crank, but I never did see one up close.  It should not be too difficult to make one out of a kitchen lazy susan base.

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