Seeking input on Turntables

[dinwitty]

The club I was in had solid homemade turntables, theres no reliance on the outer rails for support but to send current to one of the rails, the other rail current went thru the center.
The bridge was solid with the center pin plopping into the bearing base.and it supports the bridge..No sideplay or slipping, ever!
Getting the outer rail perfect is just like laying hand laid track, make yourself a wooden gauge with the correct diameter, lay the wood ties, clipping them to length,
use the gauge to adjust and spike in, or solder in if using PC ties or any other holding method.

[Anonymous]

Thanks to everyone for your advice and input. Wow, I can always count on a wealth of knowledge here on the forum.

Thanks to:
-Mike Lehman for the links
-PCarrell for the scisor wye, I've never seen one before
-David for the Peco suggestion, I'm gonna have a look
-and beegle55, I just may to that...but I'm gonna investigate options first.

Trevor

[Anonymous]

QUOTE: Originally posted by selector

Also, and not to quibble, you can't turn an entire train on a turntable unless you use a lot of track an keep one switcher very busy. Only the locomotives get turned, most often, although some cars on a passenger train were turned/relocated on the train. That is why you really should reconsider the reversing loop, particularly if you can make it part of the scenery. All it takes is two gapped ends and a DPDT that you have to remember to throw once the train is fully within the span between the gaps. If you forget, you'll get instant remedial training.

[2c]

Selector...LOL!!!! You're too funny! I know the TT is only for loco's. That's for the chuckle though.

Trevor

[selector]

QUOTE: Originally posted by dinwitty

If I dont find a reasonable priced kit, (Bowser has one) I will scratchbuild mine.
You just start with a plywood base, circle cut it, drop it down for the pit and go from there.
Find a store that sells low speed motors and gears to make a drive for it. Forget indexing, the prototype dont do it, its all eyeballing.

I agree. The 90'er that Walthers sells has a DC motor running the big black plastic ring gear, and mine runs just fine on the DC posts of an otherwise unused transformer. I dial the voltage up and down as I would for a locomotive on DC, and the motor acts accordingly. I go slow so that the drive is very quiet, the train takes about 40 seconds to be turned 90 deg, probably slow for the prototype..,who cares...and I eyeball every stall track and approach track meet to get them lined up.

If there is one thing that could go wrong, it is that the locomotive will sometimes cause the bridge to slip sideways as it enters it, with the inevitable D'OH!!! A determined modeler might construct some sort of pin-stay system at each bay track and at the approach so that the bridge cannot slip.

[ereimer]

if you look at the price of the Walthers turntable ($299.99 list , easy to find discounted for about $250) it's really not that bad for an assembled , motorized , indexed turntable .

[Anonymous]

sounds good, Beasly. I will start with taking an old record player apart (the easy part - lol) Not sure whether i understand your synchro motor-concept, though.
I had something like this in mind:

Would this have disadvantages compared to a synchro motor set-up?

[oleirish]

QUOTE: Originally posted by jrbernier

That 'cheesy' Atlas turntable is a rock solid performer! I use the Atlas TT for my 'base' and it drives a 12"(90') Walthers TT above it.

Jim

Jim
could you do some pictures up of your atlas working an 12'' walthers,and do you think it could work an 130' walthers???[?][:)]
Jim

[MisterBeasley]

QUOTE: Originally posted by dothinker

- what would be left of the turntable? The bearings?

Actually, the bearings and associated mounting framework is the part that's most needed. I would mount the disk underneath a false pit base, and only have a small opening in the center to attach the bridge. I'd keep the large platter of the record turntable to provide a heavy, stable mass. With a good set of bearings, a very small DC motor can easily turn the whole thing. After thinking about the original motor, though, you're right that it wouldn't be much use. It's going to be AC, and you wouldn't be able to control either the speed or the direction.

A pair of synchro motors would make a nice drive for this kind of thing. One motor is used for the drive, and the other for the control, mounted on your panel. By turning the shaft of the "control" motor with a handwheel, you will drive the turntable drive motor at the same rate.

[Anonymous]

MODIFIED ATLAS TURNTABLE PROJECT

Atricle in model Railroader February 1987 An inexpensive, easy to build turntable

[Anonymous]

I don't think a record turntable will cut it. Gearing it down will make it too heavy for its little motor. So, replace the gear, replace the motor, yes, oh and get rid of the needle, sure - what would be left of the turntable? The bearings? As to ready mades; the Atlas is too short, the Walthers too long & expensive, Bowsers look nice but shipping one to the Netherlands (where I live) will make it as expensive as a Walthers, which, again, is too long. Sheesh.
Rik

[SpaceMouse]

QUOTE: Originally posted by MisterBeasley

How about an old 33-and-a-third record player? It's even called a "turntable." You could mount it below the layout, and just bring up a thin cylinder in the center for the bridge drive. You could use a small motor with a friction drive on the outside, which would give you the gear reduction you want. Or, you might be able to either replace the original motor or gear it down some more.

Heck, go for broke. Use a 78 RPM. You can even play roundhouse roulette. Run it for 20 seconds to get it up to speed and let it coast to a stop. The loco then gets the track it's pointing towards.

Edit: You might want to let the engineer and brakemen get out, or you might have an awful mess in the cab.

[beegle55]

Just get the cheap and reliable Atlas and turn it into what you want using paints and scenery, maybe some extra parts. Dont try to scratchbuild or waist money.

[MisterBeasley]

How about an old 33-and-a-third record player? It's even called a "turntable." You could mount it below the layout, and just bring up a thin cylinder in the center for the bridge drive. You could use a small motor with a friction drive on the outside, which would give you the gear reduction you want. Or, you might be able to either replace the original motor or gear it down some more.

[Anonymous]

hey dinwitty, that's exactly my train of thought! A friend of mine has all the tools to cut the pit. My biggest headache is how to get the pit rail round - not just a little round, but _exactly_ round... I'm now thinking of squeezing some metal strip between two parts of the pit bottom that fit into eachother save for the thickness of the strip. Curious to know how you would get that rail round.

For the gear, still no clue. I'm thinking heavy, belt-driven, 1:1000 - like ratio, to be able to let the bridge creep along at imperceptibly slow speed. But where to find it? I'm afraid that the heavier, the more engineering it will need, like some kind of bearings (bicylce type?) on the axles of the gear wheels, etc... Maybe old car parts can do?

[dinwitty]

If I dont find a reasonable priced kit, (Bowser has one) I will scratchbuild mine.
You just start with a plywood base, circle cut it, drop it down for the pit and go from there.
Find a store that sells low speed motors and gears to make a drive for it. Forget indexing, the prototype dont do it, its all eyeballing.

[hdtvnut]

I'm using a 130 ft Diamond Scale, bought already built from someone
changing to O gauge. It is extremely solid and rigid. However, I
took off the stock drive system with its pain-in-the-butt indexing
system in favor of a Micro Design electronic positioner.

The only problem has been with heavy all-metal locos like the Trix
Big Boy. The MD belt drive can sometimes slip with these despite
everything I've tried. Needs more investigation.

Hal

[BR60103]

Trevor:
I have a pair of Peco turntables. They have a 12" bridge and automatic polarity reverse. They are not motorized. They are British prototype, but to me they look bettr than the Atlas.

[pcarrell]

There is one type of wye that most people don't normally think of. It's a Scissor Wye configuration. It's longer and skinnier then a standard wye, so sometimes it will work when others don't. Plus it looks unique. It looks like this;

[jrbernier]

The modification I used was on the Atlas Forum - search there in user FULLSCALEPILOT and WORKING - you will see how he did it. I used it and I have a great working TT.....

Jim

[mlehman]

Atlas is a viable budget-conscious choice, but if you have the resources, Diamond Scale makes some nice turntable kits. They build up nicely, but do require careful assembly. I've got the basic assembly of mine done and will be finishing the track, wiring and details this summer. Here's a link:
http://www.diamond-scale.com/

These turntables can be turned either manually or with a motor. It's not cheap, but New York Railway Supply makes a very nice, easy to use motor control system:
http://www.nyrs.com/

Mike Lehman
Urbana, IL

[selector]

Also, and not to quibble, you can't turn an entire train on a turntable unless you use a lot of track an keep one switcher very busy. Only the locomotives get turned, most often, although some cars on a passenger train were turned/relocated on the train. That is why you really should reconsider the reversing loop, particularly if you can make it part of the scenery. All it takes is two gapped ends and a DPDT that you have to remember to throw once the train is fully within the span between the gaps. If you forget, you'll get instant remedial training.

[2c]

[MisterBeasley]

This thread has been running on Layouts and Layout Building the last couple of days:

http://www.trains.com/community/forum/topic.asp?TOPIC_ID=63941

There is a lot of info about the venerable Atlas turntable, plus some pictures and some links on dressing it up.

[Anonymous]

If you are modeling a Canadian railroad, the Atlas is a model of a style of turntable used in snowy climates. A pit would have to be constantly cleared of snow. As Jim says, it's reliable. They can be dressed up very nice.
The thing you have to accept is the indexing. You may not like it stopping every 15 or 30 degrees (old models stop at every 30 degrees).

[jrbernier]

That 'cheesy' Atlas turntable is a rock solid performer! I use the Atlas TT for my 'base' and it drives a 12"(90') Walthers TT above it.

Jim

[Anonymous]

I have been trying to figure a way to turn my trains without using a turntable, but try as I might, I simply do not have the space for a "wye", and do not want to use a reverse loop. So it looks like I have to install a turntable.

Now that I have accepted this fact, I am blown away at the cost of the "more realistic" looking models (Heljan, Walters, et al). The cheesy little Atlas one is about the size I want, and certainly is inexpensive. Is there a turntable similar in size to the Atlas one which looks more realistic? Alternatively, how difficult would it be to scratch build, given that I am an intermediate level modeller? Are there plans out there for scratch building a turntable?

I look forward to your input.

Trevor