# Body mounted couplers in N scale...opinions?



## Brakeman Jake (Mar 8, 2009)

I understand that N scale manufacturers have elected to use truck mounted couplers to allow their rolling stock to handle very tight curves,in fact much tighter curves than the prototypes.I also suspect that overhang could be a problem but since I've never experimented with body mounted couplers,I'm enquiring with people who've done it and read what they say.

If feasible or even recommended,then wich pre-assembled coupler would suit best for the purpose?I visited Micro-Trains website and ended up more confused than before.They have a good product but their website is a mess of hard to find infos.Wich would be a preferably universal coupler?


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## traction fan (Oct 5, 2014)

*N-scale couplers*



Brakeman Jake said:


> I understand that N scale manufacturers have elected to use truck mounted couplers to allow their rolling stock to handle very tight curves,in fact much tighter curves than the prototypes.I also suspect that overhang could be a problem but since I've never experimented with body mounted couplers,I'm enquiring with people who've done it and read what they say.
> 
> If feasible or even recommended,then wich pre-assembled coupler would suit best for the purpose?I visited Micro-Trains website and ended up more confused than before.They have a good product but their website is a mess of hard to find infos.Wich would be a preferably universal coupler?


Brakeman Jake;

You are right. Truck-mounted couplers do help the trains handle tight curves. The curved track sections included in most train sets are usually a tight radius. In N-scale they're typically 9-3/4" radius. In an HO-scale set usually 18" radius. Both these curves, in fact virtually all model railroad curves, are way tighter than most any curves found on a full-sized railroad. (They "cheat", by having the whole wide world as "modeling space." :smilie_auslachen This is simply not possible on a model railroad. Our curves have to be tighter than the prototype's in order to fit inside a house, let alone on a typical train table. 
But, how tight are model curves, and how does the coupler mounting location affect operation on those curves? On a practical level, either truck mounted, or body mounted couplers will work on most model curves as long as the train is being pulled forward, and you do all your actual coupling of cars, on straight track. 
When we need to push a string of cars, backward; then the number, direction, and radius, of the curves can influence operation, and even cause derailments. This is where body mounted couplers have an advantage over truck mounted ones.
Pushing a train with truck mounted couplers puts the pushing force of the locomotive through the trucks. Some of that force is exerted sideways on the projecting coupler mounts when the cars are traveling on a curve. The projecting tab the couplers are mounted on, acts as a powerful lever, and tries to push the truck's wheels sideways into the rail. Since the wheels can't actually move through the rail, they climb over it and derail the car. Derailments don't necessarily happen every time a train backs through a curve. How often depends on the curve's radius, and whether, or not any reverse curves are involved. 
Backing onto a typical siding often means backing through a reverse curve. The car first travels left on the curved track built into some turnouts (Atlas "snap switches" are one example) and then must travel right through the curved section needed to bring the siding back parallel to the main line. Using turnouts that don't have curved track (Peco, Walthers, Micro Engineering, and some other Atlas) or inserting a section of straight track between the left and right hand curves, or designing the siding to maintain the same direction of curvature as the turnout, can all be used to mitigate the effect.
Body mounted couplers put all the pushing and pulling forces through the car's under-frame. These forces are not applied to the trucks. Body mounted couplers, on long cars, can push outward on the frames of the cars, rather than the trucks, when rounding a tight radius curve though.
If your railroad needs tight radius curves to fit your space, Then I would recommend truck mounted couplers and using all the tricks mentioned to mitigate the sideways force. 
If the curves can be larger, (my N-scale railroad's minimum is 16" for example) then by all means make the curve radii as big as you can, In that case body-mounted couplers would both operate, and look, better. (I use body mounted couplers.)
As for a coupler recommendation, yes Micro-Trains.
Universal coupler? There is/is not one. Is, because the Micro-Trains coupler knuckles are the same, but is not, because the mounting options differ to fit different situations. Flat cars may need to have offset shanks, since their couplers often need to be mounted to a lower surface than say, a box car's. Basic pre-assembled couplers with the smallest "draft gear" (mounting box that holds the coupler) should fit most cars. By the way, I've discovered, the hard way, that pre-assembled couplers don't always stay assembled! I now use a small soldering iron to "weld" the tabs that hold the coupler box together, or at least, are supposed to.

regards;

Traction Fan:smilie_daumenpos:
http://www.modeltrainforum.com/showthread.php?t=135313


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## GNfan (Jun 3, 2016)

*As long as I'm logged in . . . *
I prefer body-mounted couplers when I buy (maybe I should say collect) rolling stock; but if something I want has truck-mounted couplers it isn't a deal-breaker, especially if it's long.


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## Brakeman Jake (Mar 8, 2009)

It's not so much because I prefer the looks of body mounted,I don't really mind this much.It's because I could install pre-assembled knuckle couplers wich can't be done with truck mounted couplers.Assembling MT couplers is a nightmare to me.

The other solution is swapping the trucks for MT ones wich I don't like much.On top of the cost for a 100+ cars,they come with plastic wheels and have a tendency to lose axles now and then in turnouts.


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## traction fan (Oct 5, 2014)

*Loosing axles?*



Brakeman Jake said:


> It's not so much because I prefer the looks of body mounted,I don't really mind this much.It's because I could install pre-assembled knuckle couplers wich can't be done with truck mounted couplers.Assembling MT couplers is a nightmare to me.
> 
> The other solution is swapping the trucks for MT ones wich I don't like much.On top of the cost for a 100+ cars,they come with plastic wheels and have a tendency to lose axles now and then in turnouts.


 Brakeman Jake;

I understand your preference for body-mounting pre-assembled couplers. That makes perfect sense, given that you don't want to assemble couplers.
What seems weird to me is the idea of any truck, whether equipped with plastic, or metal, wheels having the wheels fall out of the truck frame on turnouts. I've never heard of that happening before. There are different axle lengths on wheel-sets. If an axle is installed in the wrong brand of truck, it can fall out, (anywhere, not just on turnouts) or not turn very well, depending on whether the axle is too short, or too long for that truck frame.
As an example, I use Micro-Trains trucks, but replace their plastic wheels with metal ones from Fox Valley Models. Fox Valley, and other companies, offer different wheel-sets to fit different brands of trucks; the basic difference being axle length. I simply buy those that are made to fit Micro-Trains trucks. 
A turnout shouldn't be able to pull a wheel-set out of a truck frame, unless something is out of adjustment on the turnout, the wheel/truck assembly or both. Checking the adjustment of all track, turnouts, and wheels should eliminate the problem; unless the axle length is, in fact, too short for the truck it's mounted in. Often a bit of gentle bending of the truck frame will tighten it up enough to work.

Good luck;

Traction Fan:smilie_daumenpos:


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