Turntable to turn the entire train!

[scottychaos]

Im working on a trackplan for my future On2 model railroad:

http://gold.mylargescale.com/Scottychaos/On2layout/index.html

Only in the planning stages so far..no actual construction has begun yet.

This is going to be a On2 scale model railroad.."Maine 2-foot gauge" trains in O-scale...similar to On30 narrow gauge in concept.

Im having trouble with the possible methods to turn my trains in the "unfinished" portion of the layout..It's important to keep a 7-foot diameter minimum, 42" radius, for good operation, this should ideally also extend to the reverse loops...well the 7' reverse loops dont really fit well..and I dont think the 4-foot diameter reverse loops will work..too tight.

I dont care for the "around the walls" idea either..because then the trains only run in a continious circle, rather than coming back to their place or origin..I like the reverse loops much better from an operational standpoint.

So, instead of the reverse loops, what about two turntables that would turn the WHOLE train?! im sure someone has done this before..(is there a name for it? I googled it but couldnt find anything...) a 4 or 5 foot turntable could turn an entire train, rather than the reverse loop..yes, I realise this would limit the length of train I could run..but these are Maine 2-footers..I probably wouldnt run a train longer than 5-feet anyway!

these turntables would be in the "hidden" part of the layout..not scenicked and not part of the "visable" railroad..im sure technology exists to do the indexing and all that..they could ride on a loop of HO scale flextrack around the edge.

anyone seen this idea done before? any good links or ideas?

 

thanks,

Scot

 

[MisterBeasley]

It would work, if you spent enough time making sure everything is aligned properly, but it's still going to occupy a large amount of real estate.

Have you thought of a "casette" arrangement?  Think of it as a car float, or barge with a track on it.  It would have to be a long as the train, but only a couple of inches wide.  Run the train on to the casette, remove it from the "dock," and turn it around and re-dock it at the other end of the casette.  This is a lot simpler than a turntable, and takes up far less space.

One thing I might do to make the rotation easier is to mount a section of metal channel in the table, running straight out from the "dock."  The casette would have a pin in one end which goes down into the channel.  Then, you can simply rotate the casette 90 degrees around the pin as a pivot, slide the pin end down the channel until the casette is at the other end, and rotate the casette the remaining 90 degrees.

 

[ChrisNH]

I have seen several versions. Its not an uncommon practice for UK layouts, I understand. I am sure someone can post some specific references.

However, a 5 foot diameter circle is a pretty big piece if realestate, hidden or otherwise. I am not sure how heavy the On30 models are.. but would a casette system perhaps take less space and provide the same function? Also.. do you need to turn the whole train or could you use two staging tracks connected to a turntable at one end to turn the locomotive?

Chris

[rrinker]

 I question the need for 42" radius curves, sure it's O scale, but 2 foot guage will be narrower than HO track, and the cars and locos are all short. But if you've tested it...

 I have seen full lengh turntables in articles over the years in MR and RMC. Can't off the top of my head name a particualr issue month and year that you could look in, but the Index might help. It's certainly a workable idea, if you have room to spin something like that around. There's also the sector plate approach, although that doesn't totally spin the train around. Perhaps a combination of a sector plate for holdign the trains and a slightly longer than usual turntable to spin the loco and a head end car or two.

 

                                --Randy

 

[Semper Vaporo]

If he is running cabooseless trains then turning just the engine is doable, but requires switching operations to do so, add a caboose and you double the yard work.  The Cassette system (car float) requires more "Hands on" and could never be automated... besides you still need the room to pick it up and rotate it; granted that could be done in a tight space, maybe even using the doorway and shoving the end into the hall outside the train room, so maybe the space requirements are a bit less, but it sure sounds like an awful lot of trouble to keep the train from falling off the cassette while it is manhandled around the door casing and someone carrying the laundry down the hall! :-)

[Midnight Railroader]

42" min radius? For On2?

Good gravy, On30 and On3 modelers get good results (operational and visual) with curves half that radius! My On30 layout has 22" radius curves with no problem whatsoever, and the trains look fine on them.

You could use an 18" min radius reversing loop with no problem and with a lot less wasted space than a massive turntable. If it's hidden anyway, why waste the time, effort and money designing something this difficult when you don't need to?

[ChrisNH]

Thats a good point.. hidden curves only need be the min for mechanical reliability.. the mice won't mind the locomotive overhang..

Chris

[Johnnny_reb]

How about placing some staging on the reversing loops? If you make the loops double or triple tracks, you could use the extra loops as staging. Besides a "Full Train" turntable would take up the same space and require more work. By using reversing loop staging you kill two birds with one stone.

Or you could combine the two plans;

trackplan09-wholebasement01.gif

and

trackplan09-wholebasement02.gif

With a reversing loop with staging "lower right of trackplan09-wholebasement01.gif

and the outside room run around "of trackplan09-wholebasement02.gif

then use a lift-out bridge at the doorway.  

[scottychaos]

Thanks for the ideas so far guys!

I was answer the diameter questions first!

 

You could use an 18" min radius reversing loop with no problem and with a lot less wasted space than a massive turntable. If it's hidden anyway, why waste the time, effort and money designing something this difficult when you don't need to?

no..impossible..Maine 2-footers are LONG..long cars and long locomotives..the real Maine 2-foot railroads had very gentle curves, and their locomotives evolved to adapt to that..even though the track is narrower than On30 (HO) they actually require wider curves than most On30 trains..

7 and 8-foot diameter is standard for Maine-2foot modeling in On2..anything narrower just isnt feasable..these arent industrial critters!  the narrow width of the track gauge really has no bearing on how tight the curves can be..believe me, tighter curves would make my planning a lot easier!  but I know for a fact I really need to run curves this wide..I was hoping to use 8-foot diameter minimum but had to go down to the "tight" 7-foot instead..thats the absolute tightest I can go and still run the scale On2 models I want to run..This is "Proto-48" On2..

so thanks..but I know what im doing as far as the diameter is concerned!  tighter curves really are not an option..

 

Back to the turntables..

Here are a few new drawings I just whipped up..first, the problem with 7-foot reverse loops..its not only the loops themselves..its also the approach tracks that have to have the same radius:

and I want these to be removable! stored out of the way when the railroad is not in use..(a practical matter for family use of the basement..)This is why im considering alternatives to the loops...

Here is my concept for the turntables:

its hard to get the full idea from a 2-D drawing..but there will be a wall down both edges of the turntable bridge..say 1 or 2 inches high..to keep the train from falling off sideways..

then..to prevent the train from running off the end of the bridge and hitting the floor four feet below, there will be an outer wall that will form a barrier to the end of the bridge as it turns..this wall does move with the bridge, it is static and is attached to the 3-foot diameter "turntable pit" section...so that the train will be unable to fall off in any direction as it turns..it cant fall sideways, or off either end.

The whole mess will only be about 6-12" thick, and can hoisted up to the ceiling when not in use..(or laid up against a wall..even easier)..it will sit on a 4-foot tall support while in use, to bring it to the same height as the layout..the "base" can just be stored wherever..maybe even collapsable.. 

 

I know there are indexing programs (DCC) that can be used with "normal" turntables..normal locomotive turntables right on a layout..I dont see why such a system couldnt be adapted to these turntables..length of the bridge is irrelevant..

so thats my thought process so far.. 

thanks,

Scot

 

[Semper Vaporo]

The center of the turntable does not need to be in the center of the space it occupies!

"NUTZ!" I hear you say I am?

Suppose your RR is in a narrow hallway with room only for the track down one wall.  Mount a turntable at each end, against the wall. The turntable bridge is rigid enough to support the ends from just the center pivot.

The center pivot is mounted on one end of an arm that is just slightly longer than 1/2 the turntable span. The other end of the arm pivots at the end of the lead track to the turntable.

To turn the entire train, pull onto the turntable bridge and swing the arm out, rotate the turntable and swing it back in to align the other end of the turntable with the lead track.

Granted, the width of the space needs to be as wide as the turntable is long, but the space is only occupied while the train is being turned and is free for people to walk past the rest of the time.

???

[tomikawaTT]

Hi, Scott,

The full-train turntable is a common phenomenon on minimalist railroads in the UK and elsewhere, just not often used in the US.

It would be possible to rig the turntable to lay along the wall for loading and unloading, then pull the pivot point out far enough to swing the table end for end.  That way the pivot point would only occupy aisle space for a few seconds.  Providing enough clearance is the only consideration, and a reasonable aisleway should be adequate.  (Since I am built like a barrel, I consider a 32 inch aisleway 'reasonable.')

As for staging, there's no reason that the turntable can't have 2, 3 or more tracks.  The mating ends would have to have gentle curves to make a 'straight' connection with the fixed approach track (or tracks.)  I have seen examples with five tracks, but in smaller scales.

I am starting to wish I had considered full-length turntables for some of my hidden staging.  If nothing else, they would have eliminated a couple of hidden track puzzle palaces (multiple curved 3-way switches...)

Chuck (modeling Central Japan in September, 1964)

[dehusman]

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.

[scottychaos]

The center of the turntable does not need to be in the center of the space it occupies!

"NUTZ!" I hear you say I am?

*snip*

 

very interesting! never thought of that before..thanks! that idea could be useful..

Scot

[Midnight Railroader]

You could use an 18" min radius reversing loop with no problem and with a lot less wasted space than a massive turntable. If it's hidden anyway, why waste the time, effort and money designing something this difficult when you don't need to?

no..impossible..Maine 2-footers are LONG..long cars and long locomotives..the real Maine 2-foot railroads had very gentle curves, and their locomotives evolved to adapt to that..even though the track is narrower than On30 (HO) they actually require wider curves than most On30 trains..

I am well aware of what Maine 2-footers look like and what kind of minimum radius they require.

You, on the other hand, seem to think On30 is the land of critters and shorty cars. I invite you to learn about the 2-8-0s and even compound steam that run on On30 layouts, pulling scale-length passenger cars before you judge.

The "real Maine 2-foot railroads" did not, to my knowledge, have full-train length turntables, but you'll accept that, so using a hidden turnback loop of less than your preferred min radius shouldn't be  a problem, either.

It's not "impossible."

[scottychaos]

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.

yes, I could turn the locomotive itself on a "normal" turntable..but would also have to switch the caboose to the other end of the train..

that would require operation in the "unfinished" part of the layoout im not really interested in doing..

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! 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.

Im imaging this layout can be operated by one person running two mainline trains at once..or two people each running one mainline train..perhaps at most a third person running a local..it will mostly be a one-man operation..just me.

So with these reverse loops (or turntables) you always have two trains switching directions and "coming back at you"..they will have to be stopped and moved around each other on a passing siding..I dont want to have to always be going into the other part of the basement to switch the engines and cabooses around before the trains can come back..

Im not really interested in staging..not a concern at this point..although that is a good idea to add extra tracks for future use..if I do ever want some staging..

Scot

[scottychaos]

You could use an 18" min radius reversing loop with no problem and with a lot less wasted space than a massive turntable. If it's hidden anyway, why waste the time, effort and money designing something this difficult when you don't need to?

no..impossible..Maine 2-footers are LONG..long cars and long locomotives..the real Maine 2-foot railroads had very gentle curves, and their locomotives evolved to adapt to that..even though the track is narrower than On30 (HO) they actually require wider curves than most On30 trains..

I am well aware of what Maine 2-footers look like and what kind of minimum radius they require.

You, on the other hand, seem to think On30 is the land of critters and shorty cars. I invite you to learn about the 2-8-0s and even compound steam that run on On30 layouts, pulling scale-length passenger cars before you judge.

The "real Maine 2-foot railroads" did not, to my knowledge, have full-train length turntables, but you'll accept that, so using a hidden turnback loop of less than your preferred min radius shouldn't be  a problem, either.

It's not "impossible."

 

I dont really wish to debate it..not relevant to the discussion.

thanks anyway..

Scot

[Semper Vaporo]

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.

 

Turning the whole train means you don't have to uncouple the engine AND the caboose, turn them both (separate operations) and reattach them to the rest of the train.  That is a FUN thing to do for sure, but is VERY difficult to automate and way too much trouble if all you want to do is make the train run the other direction in the "Viewable" portion of the layout (and not have it backing up through sceniced countryside 1/2 the time).

[Midnight Railroader]

You could use an 18" min radius reversing loop with no problem and with a lot less wasted space than a massive turntable. If it's hidden anyway, why waste the time, effort and money designing something this difficult when you don't need to?

no..impossible..Maine 2-footers are LONG..long cars and long locomotives..the real Maine 2-foot railroads had very gentle curves, and their locomotives evolved to adapt to that..even though the track is narrower than On30 (HO) they actually require wider curves than most On30 trains..

I am well aware of what Maine 2-footers look like and what kind of minimum radius they require.

You, on the other hand, seem to think On30 is the land of critters and shorty cars. I invite you to learn about the 2-8-0s and even compound steam that run on On30 layouts, pulling scale-length passenger cars before you judge.

The "real Maine 2-foot railroads" did not, to my knowledge, have full-train length turntables, but you'll accept that, so using a hidden turnback loop of less than your preferred min radius shouldn't be  a problem, either.

It's not "impossible."

 

I dont really wish to debate it..not relevant to the discussion.

thanks anyway..

Scot

Okay, thanks for asking for help.

[ndbprr]

I guess my thought process is why?  Freight cars are double ended and most coachs had walkover seats so the passenger could always face forward.  You might also want to consider a wye as it might be able to be fit somewhere better than a trntable.

[scottychaos]

Thanks everyone!

So it sounds like there are no logistical reasons why the turntables couldnt work..Im liking this idea a lot more than the reverse loops now! it might be a bit more complicated to construct..but nothing too difficult..

How about automatic DCC "turntable turners" then?

Im relatively new to DCC..only picked it when when I started in On2 a few years ago..

(I modeled in HO scale as a teenager back in the 80's..but no DCC to speak of then! ;)

Right now I have a NCE powercab, if it matters.. 

Are there DCC systems that would allow a train to run onto these turntables, automatically stop, turn the table 180 degrees, and then have the train come back out? what about alignment mechanisms? Im sure some kind of existing system for a "normal" turntable could be adapted somehow..but as I said, Im new to DCC.. 

thanks!

Scot 

[el-capitan]

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! 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.

 

[Semper Vaporo]

I guess my thought process is why?  Freight cars are double ended and most coachs had walkover seats so the passenger could always face forward.  You might also want to consider a wye as it might be able to be fit somewhere better than a trntable.

A Wye would work, but still takes permanent space.

If you don't turn the whole train, you have to:

1: pull into the staging area and stop,
2: uncouple the engine,
3: pull forward onto a short turntable or wye to make the engine face the other way,
4: run down a parallel runaround track,
5: throw a switch to get on the same line as the rest of the train,
6: pull onto the main line,
7: throw the switch back,
8: back to and couple to the caboose,
9: uncouple the caboose from the train,
10: pull the caboose ahead past the switch to the runaround,
11: throw the switch to the runaround,
12: shove the caboose to the runaround and uncouple from it,
13: pull forward past the switch,
14: throw the switch again to the mainline,
15: back to the train and couple to it,
16: pull forward until the rear of the train is past the switch,
17: throw the switch again to the runaround,
18: back the train to the caboose and couple to it.

Now you can pull from the staging area to the sceniced area of the layout to see the train go the otherway.

There would be a few more steps if you want the caboose reversed also... the rear brakeman usually wanted the caboose stove chimney behind him so the smoke from it did not obscure his view from the coupola.

Using a whole train turntable could be automated in an out-of-sight staging area.  Automating that 18(plus) step sequence might be fun to do, but I think the whole train turntable would be a bit easier.

 

[cacole]

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.

[tinman1]

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.

[scottychaos]

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! 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!

just need to figure out how..

Scot 

 

[el-capitan]

 

I bet someone somewhere has done this already!

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.

[loathar]

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.

[R. T. POTEET]

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.

[ChrisNH]

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

[dknelson]

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