As John and others said, Kadees work great and they are the only couplers I use…
Nick
Andy has got it right. Korm isnt necessarily wrong, in his example he is using an extreme curve and that is where truck mounted couplers work better.
I say stick with the truck mounted ones for now. If you dont want to worry about derailments by backing heavy trains then eventually you will want to go to body mounted ones. Keep in mind there is a height difference, so if you dont want to convert all of your rolling stock at once, you can create a car that has body mounted on one side and truck mounted on the other.
I personally have had good luck with truck mounted. Having said that, the amount of force on them (trying to twist the truck as much as push) is the real concern. I don’t have enough track (or rolling stock) to worry about a 20 car string, so they work fine for my purposes.
On relatively flat track the truck mounts will back just fine, but take heed to the proper weight of your cars (Fr. Fred is the expert on that one, and there is a thread here o that subject) and push in a realistic manner and you won’t experience alot of problems. As Andy said there are pros and cons on either side of this one. Jumping from 0 to 20 scale miles an hour around a curve, on a grade will pretty much lay about any rolling stock on its side, certainly a 20 car train, as an extreme example.
Ken Brunt said:
Korm Kormsen said:
If ya’ shove two helpers in the middle and on the end ( EMD units geeps or Sd’s) then you might be able to make that grade and radius…
Oh crap…sorry thats a top view not a side view…
David, sometimes you crack me up.
I would get a headache trying to program the revolution (thats what I have) for mMU’ing 2, let alone the at least 4 you are talking about. That would seem to get not fun pretty quickly…
I have all truck mounted couplers except three short freight cars (Aristo) which are body mounted. I do not run long trains - no more than seven cars - so experience few issues, incorrectly aligned switches being the principal cause.
I realize body mounting is prototypical but have kept to truck mounted couplers. This has allowed me to sell some of my stock on occasions to new comers to the hobby more or less in the condition, with box of course, that they would buy when new. I am sure many of us have purchased rolling stock which we find does not fit in well with our present type of operations.
My standard coupler is Aristo (1:29) type: these are also fitted to my Big Hauler stock. The original Bachmann couplers look better but do, after time it seems, develop a weakness.
In a couple of places we have added passing sidings, so the engine could run around a pull of cars that are hard to shove up a hill. Many times the solution is to work around the problem to resolve it. If a person has a large inventory of rolling stock, it takes time to do all the maintenance and modifications to bring to a common standard. Then of course you have visiting equipment and all the mods are sometimes out the window. Sometimes basement windows. 
Andy Clarke said:sure. the drawing is exagerated to dramatize the effects visually. and sure, someone with a layout, that has 20ft. diameter curves as minimum does not need to think twice about the strength of sideways forces. what i wrote is based on my own experience. and that includes lots of R1 curves and semicircles.
One of the problems with those drawings is the fact of scale.... ..., which greatly exagerates the shown forces....
and, yes, body mounted couplings look a lot better - but R1 curves combined with bodymounted couplings did restrict me to cars of seven and a half inches “long” carbodies. (even for my wild west theme that is a wee bit too short!)
Korm Kormsen said:
................... what i wrote is based on my own experience. and that includes lots of R1 curves and semicircles.and, yes, body mounted couplings look a lot better - but R1 curves combined with bodymounted couplings did restrict me to cars of seven and a half inches “long” carbodies. (even for my wild west theme that is a wee bit too short!)
Hi Korm,
R1…hmmm. For that I would recommend the original LGB “Bottle Openers”, BUT I also know from experience that they work like sh… when pushing a string of cars through R1 turnouts.
Been there, tried that and decided to rebuild my complete Staging set-up. Everywhere else I already used 1500mm as the minimum radius.
As the saying goes if you use original LGB equipment on original LGB R1 track with all original LGB couplers and it doesn’t work … well then you decide to work to a standard that’s a few steps up from the TOY level! 
HJ, the bottleopeners have just one problem. they are often fixed to one-aixle-trucks. with the result, that some of the lighter cars try to run with wheels, that run at an angle to the rails. but there is a simple remedy to that.
(http://kormsen.ko.funpic.de/bahn/forumpics/achslenkung1.JPG)
1500mm radius? - i am happy, when i am able to have that number as diameter! did you note the third drawing on the pic, up there some postings ago? that is a very safe manner to couple short cars for sharp curves. i used that on my homebuilt cars with fixed aixles. helps to evade the long distances between cars too. (nothing for shunting layouts!)
Well…it occurs to me that one way to avoid having to decide between body-mounts and truck-mounts is to put both on the same car (at the same time):
(http://freightsheds.largescalecentral.com/users/dawgnabbit/misc/af1.JPG)
Of course, a little special engineering of the underframe is required:
(http://freightsheds.largescalecentral.com/users/dawgnabbit/misc/af2.JPG)
FWIW, I built these articulated flatcars to be consistent with the fictional backstory of the DC&M. They’re designed to get around the too-tight curves in the ballast washing and bagging plant at Wash. Steve
cute design… 
Now Steve, with that design surly you could use body mount knuckle couplers. (grin)
Yeah, Rick…I guess that’s what this thread is all about, isn’t it.
OK, I have read over what you all have had to say on this subject. I started R2 and R3 LGB curved track on the chicken house layout in Germany. I then bult a few cars out of wood and used body mounted KaDees with out a lot of trouble. Now that I am at home (USA) I built in the yard with nice large radius curves (6 foot or better). Since run on the CCRy, I use truck mounted couplers (Bachmann) and have had no problems pushing as well as pulling a string of cars, now keep in mind that these are not light cars. Operstions on the CCRy requires forward and back moves as well as nose moves without any problems. I do have a test set of 3 scratch built box cars with body mounts (Kadees) in the center (car) and I have run that on my ROW as well the CCRy without any problems.
Keep in mind that I use steel wheels and aome times some weight in the cars. Also, keep the curves and transitions smooth. I use rail clamps on the curves and the track in screwed down to PT 2x6 or wider! Also, I don’t run at any kind of speed.
Paul
Steve Seitel said:
Well…it occurs to me that one way to avoid having to decide between body-mounts and truck-mounts is to put both on the same car (at the same time):(http://freightsheds.largescalecentral.com/users/dawgnabbit/misc/af1.JPG)
Of course, a little special engineering of the underframe is required:
(http://freightsheds.largescalecentral.com/users/dawgnabbit/misc/af2.JPG)
FWIW, I built these articulated flatcars to be consistent with the fictional backstory of the DC&M. They’re designed to get around the too-tight curves in the ballast washing and bagging plant at Wash.
Excellent!! Love the articular actuation with clean lines! …:)…
For what it’s worth, I too have found that truck-mounted couplers caused derailments when being pushed through curved track. I’ve had similar problems with two-axle “shorty” cars as well.
There more to the analysis than just how the coupler forces are transmitted to the body.
A huge problem is that the forces now twist the truck and make it bind in the curve, adding friction and unwanted forces that help cause derailments. This is really the biggest factor in the difference.
It’s been proven over and over in actual layouts and in short trains also, especially backing up, where you don’t have the tension of the train helping keep the trucks from being twisted sideways in the rail.
Greg
p.s. That is one hell of a cool car David!
As usually, Nice work and very interesting car…
