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Korber roundhouse & Diamond Scale turntable repairs

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Korber roundhouse & Diamond Scale turntable repairs
Posted by railandsail on Wednesday, March 4, 2020 7:45 AM

I have a turntable & roundhouse scene I purchased use from an estate sale long ago.

Turntable:
The turntable is a Diamond Scale 134 footer that may need a new pit built for it as the old one is very slightly warped, and the pit wall is cracked in a few places. I believe the pit wall is constructed of Hydrocal. How might someone go about filling in (bonding?) those cracks in the pit walls?

Roundhouse:
The roundhouse is a Korber kit that a few cracked wall sections that need reglueing. The broken sections fit together very good, but need a proper reglue. What type of material are those walls made of, and what might be the best adhesive to use??

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Posted by RR_Mel on Wednesday, March 4, 2020 8:34 AM

I have a Korber roundhouse from the 90s and it is made of a resin type of plastic.  I kitbashed my roundhouse to extend the stalls from 15” to 19½” deep.  I used super glue and it has done very well over the years.  I’ve overhauled it twice and the super glue has held very good.
 
 
I bought a second 104 kit to increase the wall length to 19½”.  I needed the extra depth to accommodate my Southern Pacific Cab Forwards.
 
 
Any AC should be hold very nicely.  The Korber Roundhouse is very nice!!!
 
Can’t help with the turntable, my turntable is a 135’ CMR Kit.
 
 
 
 
Mel
 
 
 
My Model Railroad   
 
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I'm beginning to realize that aging is not for wimps.
 
 
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Posted by railandsail on Wednesday, March 4, 2020 9:14 AM

Thanks Mel,
I usually go to superglues as a last resort, as they leave a visible sign of use (shiny spot?) . I use to really like that Tenax 7 adhesive, but I don't think that would work on this resin kit,...that I thought might be plastic at first.

I think I am going to have to get rid of the 'composite board pit' of the original Diamond Scale and replace it with a thick plywood or 'foamed PVC'. Then I think I will make the pit walls out of a thinner strip of bendable plastic or that same 'foamed PVC'.    get rid of the hydrocal pit wall.

PS: I'm real happen that I discovered that I have almost all the 'pieces' of this roundhouse, rather than going out searching for some new kit. Its going to be a bit of a challenge to get it all back together as even the roof sections are warped (and likely in need of replacement), but in the end it is a nice kit.

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Posted by doctorwayne on Wednesday, March 4, 2020 9:50 AM

I built a Diamond Scale turntable for a friend, and while it turned out well, the pit was  out-of-round, and required quite a bit of sanding to allow full rotation of the bridge.

I also have a Korber roundhouse, but with only five stalls, all of them shortened.  While it eventually turned out okay, it was a bit of a job to build.
I ended-up assembling it with screws and epoxy, and discarded all of the kit-supplied material for the roof.  I also discarded the doors, replacing them with ones from Grandt Line.

Here are a few pictures...

There's a thread HERE which shows the entire sequence of construction.

Wayne

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Posted by RR_Mel on Wednesday, March 4, 2020 12:11 PM

Brian
 
If you are careful super glue gel works very good without any gloss/glue showing.  The only problems I’ve had using the gel is it takes about 2 minutes to cure.
 
 
Wayne
 
Your Korber looks to have plastic inner beam structure, mine came with Basswood, about 1995.
 
A question, do the Grandit Line doors fit the openings as is.  I’m kicking around replacing the doors on mine.  I went to automated doors a couple of years ago using an Arduino driving servos and it has become more of a hassle than it was worth.  I used the micro G7 servos mounted above the doors.  Too many problems controlling the servos and I don’t like having to operate them manually using a switch.  I haven’t closed them since a visitor wanted to see them work months ago.
 
 
 
 
 
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Posted by railandsail on Wednesday, March 4, 2020 2:50 PM

RR_Mel

Wayne
 
Your Korber looks to have plastic inner beam structure, mine came with Basswood, about 1995.


Mine must have been an early one also, as it has wooden beams.
 
RR_Mel
A question, do the Grandit Line doors fit the openings as is.  I’m kicking around replacing the doors on mine.  I went to automated doors a couple of years ago using an Arduino driving servos and it has become more of a hassle than it was worth.  I used the micro G7 servos mounted above the doors.  Too many problems controlling the servos and I don’t like having to operate them manually using a switch.  I haven’t closed them since a visitor wanted to see them work months ago.
 
 
Interesting question??.... as my 3 of my 5 door frames appeared to be warped to a significant degree,...not the doors themselves, just the frames.
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Posted by RR_Mel on Wednesday, March 4, 2020 4:08 PM

I have some small scraps of the walls that were warped slightly and laying them on a flat surface I straightened them using a hairdryer.  If that doesn’t work out you could make a mold using a good frame then pour a resin casting.  I made a rear wall casting that way for another structure.
 
 
 
Mel
 
 
 
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Posted by doctorwayne on Wednesday, March 4, 2020 10:47 PM

RR_Mel
...Wayne Your Korber looks to have plastic inner beam structure, mine came with Basswood, about 1995....

I don't recall exactly when I bought the Korber Roundhouse (Hobbies For Men - Beacon, NY.), but it was before I built the house in which I'm living (1988).  I'd guess mid-to late '70s.  It came with basswood framing, too.
While I enjoyed build a real house using wood, it's not been a favourite of mine for model building since styrene sheets, strip, and shapes became readily available.  I gave the wood to a friend who still uses it for model building.

RR_Mel
A question, do the Grandit Line doors fit the openings as is. I’m kicking around replacing the doors on mine.

Mel, as best I recall, the doors were pretty-much useable as they came.  If they needed any alterations, it would have been something very basic, like trimming the height or width.

Each door comes as two pieces, the inner and outer faces, which each have half-hinge mouldings on one edge.
When the two halves are cemented together, they create a number of hinges into which a piece of suitably-sized wire can be inserted , to act as the pivot for the door.  Here's a photo...

I used phosphor-bronze wire, bending the bottom end as a short "L", the base of which was ca'd into a hole drilled into the exterior face of the wall.  After threading each door onto its hinge wire, I formed eyelets from the same wire, slipped one onto the top of each hinge wire, and ca'd them into the wall, as shown in the photo.

I haven't had much time to work on the layout, but I'll eventually add posts between the doors, with a place to hitch the doors in an open position, as was done on this ex-Vollmer roundhouse, now one of the shop buildings at Lowbanks...

All of the doors open and close, but all are manually operated.  I normally leave them open, but occasionally close them, when appropriate, for photo-taking.

Wayne

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Posted by Doughless on Thursday, March 5, 2020 7:10 AM

RR_Mel

I have some small scraps of the walls that were warped slightly and laying them on a flat surface I straightened them using a hairdryer.  If that doesn’t work out you could make a mold using a good frame then pour a resin casting.  I made a rear wall casting that way for another structure.
 
 
 
Mel
 
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
 

If resin flattens out with the application of heat like styrene does, I've unwarped styrene walls by placing the piece in between two pieces of cheap picture frame glass, and placing the unit outside to heat up in the sun.  The glass in those frames is very thin, so finding a way to place a bit of weight on the top sheet without blocking the sunshine is the way to go.

I'm assuming Florida sun will take care of the warp in short order (hopefully not too strong as to melt the details!)

Then bring the entire unit back inot the house to cool.  I've noticed that if I remove the wall from the glass and its allowed to cool on its own, it will sometimes just warp back to where it was.  It needs to cool under the pressure to stay straight.

- Douglas

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Posted by railandsail on Thursday, March 5, 2020 10:39 PM

Interesting comments about warpage. The owner of Korber suggested putting parts in the oven, but didn't metion a tempature. I wonder how easily these parts could be damaged by heat?? I do also have a good heat gun, but I am inexperienced in using this new unit that was given to me.

Wayne,... I like the way you built it on a plastic base sheet. I think I want to try and do something like that so I can pick the whole structure up and off the layout, in order to work in those areas.

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Posted by doctorwayne on Thursday, March 5, 2020 11:13 PM

Thanks, Brian.

Making the floor an integral part of the structure made it a lot easier to handle, without fear of breakage, and it did a lot of travelling between workshop and layout during construction.

I don't recall exactly what I was up to with it in this position, sitting on its rear wall...

...and building the roof and its support structure was a real seat-of-the-pants operation, as front-to-back and stall-width measurements were all over the place, due in part to the kit components, and even moreso to my construction methods...

The roof and its support framing is removeable as a unit - handy if I ever want to detail the interior, I guess...

Wayne

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Posted by Doughless on Friday, March 6, 2020 6:01 AM

railandsail

Interesting comments about warpage. The owner of Korber suggested putting parts in the oven, but didn't metion a tempature. I wonder how easily these parts could be damaged by heat?? I do also have a good heat guy, but I am inexperienced in using this new unit that was given to me.

Wayne,... I like the way you built it on a plastic base sheet. I think I want to try and do something like that so I can pick the whole structure up and off the layout, in order to work in those areas.

 

I'd think a heat gun would work.  Of course, if the heat was concentrated for too long in one spot it might cause damage.  Placing the item under a pieces of glass, preferably 1/4 inch scrap glass that a glass shop might have (get the edges polished) would likely be enough weight to flatten the wall as it heats up and would tend to spread out the heat.

- Douglas

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Posted by RR_Mel on Friday, March 6, 2020 7:48 AM

Brian
 
I had an extra door frame but used it for making a mock up when I was tinkering around with servos to open and close the doors.
 
 
Over the years between first assembly and the mock up (about 15yrs) the door frame was a bit warped and my heat gun worked pretty good.
 
 
 
The servos (G7) fit in the overhead above the doors.
 
 
Mel
 
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
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Posted by RR_Mel on Friday, March 6, 2020 8:17 AM

I originally built my roundhouse as a single unit back in 1991 along with a scratch built turntable.  The turntable while it looked good had mechanical problems.  I replaced the Mel scratch built in 2000 with a CMR Kit and it wasn’t until 2007 before everything was installed and working.
 
 
1991
 
I built the Korber/CMR roundhouse and turntable as a one piece unit.  I didn’t think it would be possible to do the install on my layout as two separate units.  It is huge but it went off perfect first try (53” x 30”).  I have removed the assembly twice since the 2007 install for modifications and everything went very good both times.
 
 
2007 install
 
Everything is attached to ¼” plywood, surprisingly the slight flex in the plywood doesn’t ding anything while moving it around.  Sure makes it easy to work on.  The first removal was to add indexing and the second was the addition of door servos, a third is just around the corner to remove the servos and maybe change the doors out to Grandit doors.
 
 
 
Mel
 
 
 
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I'm beginning to realize that aging is not for wimps.
 
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Posted by railandsail on Friday, March 6, 2020 8:36 AM

Mel, ...neat idea to built the 2 structures as one unit, but at the moment I'm thinking they will be 2 units.

Just found this image this morning, and I really like the 'roof-less' design.....or perhaps like Wayne said, a removable 1-piece roof??

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Posted by railandsail on Friday, March 6, 2020 8:38 AM

I think I will try that glass forms with sunlight or heat gun application for the warpage.

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Posted by RR_Mel on Friday, March 6, 2020 9:12 AM

I made both roof sections one piece using bulletin board.  Much better than single sections for each stall.
 
 
 
 
 
Mel
 
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
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Posted by RR_Mel on Friday, March 6, 2020 11:09 AM

This a Mel CAD drawing of my Korber 104 Roundhouse Kitbash to accommodate my long articulateds.
 
 
 
 
 
 
 
Mel
 
 
 
My Model Railroad   
 
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I'm beginning to realize that aging is not for wimps.
 
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Posted by railandsail on Friday, April 3, 2020 8:52 AM

I got delayed with this project with a number of home projects,..but in the meantime I was thinking of alternative repairs.

1) I am now firmly convinced that I will build a new pit and pit walls using cellar PVC (also known as foamed PVC). Its basically a light weight version of solid sheet PVC. I really like this material. I'll document this rebuild with photos. I need to retrieve my router so I can cut real accurate disc of PVC and big hole in plywood deck to accept the new pit structure.

2) Still trying to determine the best method to flatten out the warped resin built doorways of the original Korber kit. I did see one reference to a method here,...
http://designbuildop.hansmanns.org/2020/03/20/flattening-a-warp/

 

 

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Posted by RR_Mel on Friday, April 3, 2020 9:07 AM

I have a five stall Korber Roundhouse #104 and I believe the walls are resin casting.  I went with regular super glue when I assembled it back in the early 90s.  I did a kitbash to lengthen the depth of the stalls to accommodate my Rivarossi Cab Forwards.  I cut the side and rear walls to add length using a second 104 kit, T used super glue and now 25 or so years later it’s still a solid structure.
 
A before and after drawing of the wall section.
 
 
 
 
My turntable is a CMR so I can’t help with that.
 
 
 
Mel
 
 
 
My Model Railroad   
 
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Posted by railandsail on Friday, April 3, 2020 9:29 AM

I recall seeing that modification you made to yours Mel,...nice job. I think I am going to leave the roof off as well. Often I am not a fan of superglues, so I'll likely stick with epoxy, particularly after finding some of it on sale yesterday at my ACE hardware.

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Posted by railandsail on Sunday, April 19, 2020 12:29 PM

DCC Wiring up Manual Turntable

What is the most simply manner to wire up Diamond Scale turntable for DCC train operations. The turntable itself will NOT be indexing, nor powered in its turning,...just simple manual rotation?

 

I suppose one power lead still needs to come in thru the tower on the bridge, while the other comes thru the circular track in the pit? And I assume this circular track does NOT have to be segmented as there are dual contact wheels at both ends of the bridge?

 

There will be 3 powered tracks coming into the turntable, and all the remaining tracks (approx 8) will be storage tracks,.... that I would wish to be dead until the bridge is selecting them.

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Posted by RR_Mel on Sunday, April 19, 2020 1:26 PM

Power to the bridge can be very troublesome, if I were you I’d check out the small slip ring assemblies on eBay.  Back when I did my thing the small slip rings weren’t available.
 
Early on (60s & 70s) I tried the split pit rail power and to me it’s worthless.  In the 80s I made a center shaft from several sizes of brass tubing for power, much better than the split pit rail but still a bit troublesome.
 
This has worked great without any problems for over 10 years but was a lot of work to build.
 
 
 
 
 
The slip ring requires a tubing shaft but once in place it will be trouble free for the life of the turntable.
 
I installed lights on my bridge and indexing IR sensors as well as rail power.  I’ve never had any problem with the connections.  I made my indexing system so that the bridge can be automated or manual operation.  I drilled a 1/16” hole in the wall of the pit below the center of each track and when the IR sensor is activated the bridge stops, perfect rail alignment (within 1/64”) every time!  No screwing around with a controller to align the rails.
 
 
 
Mel
 
 
 
My Model Railroad   
 
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I'm beginning to realize that aging is not for wimps.
 
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Posted by doctorwayne on Sunday, April 19, 2020 1:47 PM

railandsail
There will be 3 powered tracks coming into the turntable, and all the remaining tracks (approx 8) will be storage tracks,.... that I would wish to be dead until the bridge is selecting them.

I also have three tracks leading to the turntable at Mount Forest, each with the power controlled by fascia-mounted switches.  The roundhouse and garden tracks are each controlled by a setting on a rotary switch, like this one, used for the Lowbanks Shops...

There is no roundhouse at Lowbanks, but several tracks coming off the turntable and a couple, turnout-connected, all controlled via the rotary switch. 

There's also a separate ON/OFF switch and a direction switch for the turntable rails....very low-tech, but all easy to do.

Wayne

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Posted by RR_Mel on Sunday, April 19, 2020 2:02 PM

I forgot to say that I have a DPDT switch for each track.  I still operate dual mode, DC or DCC so my layout is wired for block operation.
 
 
Like Wayne, super simple.
 
 
Mel
 
 
 
My Model Railroad   
 
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I'm beginning to realize that aging is not for wimps.
 
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Posted by gmpullman on Sunday, April 19, 2020 5:06 PM

Do you have a hollow center shaft?

My Diamond Scale 130 footer has a solid shaft through the center bearing. Difficult to run wire through. Therefore I use the ring rail for one side rail and the top arch powering the other rail. Haven't had any troubles in twenty-some years.

I keep the brass truck wheels clean and give them a tiny drop of De-Oxit every now and then. When I converted to DCC this allowed me to take another pair of leads off the rails and illuminate a post lamp at each end of the bridge for the operator to see the alignment at night since the rails are hot as long as I have the toggle switch on Yes

 Q_on_TT by Edmund, on Flickr

I need to paint that brass power pole, someday. You can see one of the lamps at the left end. I should darken the bare copper top wire, too. Someday.

 

[edit]

railandsail
PS: I'm real happen that I discovered that I have almost all the 'pieces' of this roundhouse, rather than going out searching for some new kit.

BRIAN

I recently replaced my nine-stall roundhouse with a newer Walthers "Modern" roundhouse.

PM me if you could use my old, Heljan nine-stall roundhouse. I have no one around me that can use it and I hate to see it go in the land-fill.

Good Luck, Ed

 

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Posted by RR_Mel on Sunday, April 19, 2020 6:46 PM

ED
 
The CMR Turntable came with a solid shaft and I made a hollow shaft using K&S brass tubing.
 
The slip ring I made only has four contacts and my turntable uses six wires.  Two for indexing, two for lighting and the brass shaft for one rail and the overhead wire for the other rail for a total of six.
 
If I had it to do over now I would go with one of the eBay 6 wire slip rings and not use the overhead or shaft for rail power.
 
The Mel slip ring worked much better than I thought it would, it’s large and clumsy looking but it has worked flawlessly since I installed it.
 
Over the years I scratch built many turntables and had mechanical problems with all of them.  The CMR has been perfect from the get go.  The Dayton 12 volt DC .5 RPM gear motor would make any turntable work perfect!  The 7189:1 gear ratio really works great.
 
I did add an adjustable slip bushing between the gear motor and the bridge.  The motor has 50 in-lb of torque, if anything happened to stall the bridge something would have to give . . .  could toss a locomotive against the wall.
 
 
Mel
 
 
 
My Model Railroad   
 
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I'm beginning to realize that aging is not for wimps.
 
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Posted by railandsail on Monday, April 20, 2020 8:42 AM

gmpullman

Do you have a hollow center shaft?

My Diamond Scale 130 footer has a solid shaft through the center bearing. Difficult to run wire through. Therefore I use the ring rail for one side rail and the top arch powering the other rail. Haven't had any troubles in twenty-some years.

I have a solid shaft like you said, and just thought I would make a solid ring rail for the pit when I build my new pit. Got my plans pretty well laid out using cellular PVC material in place of plaster of original, and good grade plywood in place of composit wood plate of the original.

I keep the brass truck wheels clean and give them a tiny drop of De-Oxit every now and then. When I converted to DCC this allowed me to take another pair of leads off the rails and illuminate a post lamp at each end of the bridge for the operator to see the alignment at night since the rails are hot as long as I have the toggle switch on Yes


DeOx sounds like a good idea. Are you saying you power the post lamps with a connection to track power,...DCC power??

 


I recently replaced my nine-stall roundhouse with a newer Walthers "Modern" roundhouse.

PM me if you could use my old, Heljan nine-stall roundhouse. I have no one around me that can use it and I hate to see it go in the land-fill.

Good Luck, Ed

I only have space for a 5 stall roundhouse (maybe 6). Can that one of yours be cut down fairly easy?
Perhaps a private email at 'railandsail (at) gmail.com'  (I can't use the private mail on this forum as I utilize Firefox)

 

 

 

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Posted by railandsail on Monday, April 20, 2020 8:51 AM

doctorwayne

There is no roundhouse at Lowbanks, but several tracks coming off the turntable and a couple, turnout-connected, all controlled via the rotary switch. 

There's also a separate ON/OFF switch and a direction switch for the turntable rails....very low-tech, but all easy to do.

Wayne

 

Sort of what I had in mind,...two questions,...
1) Are rotary switches still available? I thought they were 'old school'.
 
2) Does this mean you need to remember if the turntable is turned 180 degrees as to matching its polarity with that of the 'powered tracks' connected to the turntable,...MEMORY required to hit the polarity switch??
 
This was suggested on another forum, but I am unsure as to whether it would work 'automatically' in this situation,..
The rails on the turntable itself at one point will be reversed as you turn it. I use a DCC Specialties PSX-AR auto reverser on the turntable tracks. Track buss to the auto reverser-auto reverser to the turntable track. No issues and works just fine.
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Posted by RR_Mel on Monday, April 20, 2020 9:58 AM

I recently bought a new rotary switch for my turntable for better spacing.  My old one was 30° spacing and I didn’t like the 210° swing for 7 tracks so I bought a 23 position rotary switch with 15° spacing. 
 
 
 
Most rotary switches have an adjustable stop and I set mine at 7 positions.  The 105° swing from the inbound yard track to the track on the right of my roundhouse looks much better.
 
 
 
 
 
Mel
 
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 

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