How to "narrow the gap" on MTL Heavyweights

[InterurbanModels]

MTL Heavyweights are by any means beautiful cars. They nevertheless have two problems, which are also linked: 1/ an awful wide gap between the cars when coupled 2/ problems when running with truck mounted couplers on Kato/Rapido/etc cars.

When addressing this problem, you have to make a choice first: going all truck mounted, or all body mounted. Every choice has it ups and downs, I choose truck mounted.

This said, you have to add then a coupler to the 6-wheel truck. Exploring the solutions, I came up with a 3D printed "copycat" truck with a functional coupler. This home designed coupler interacts with MTL, Atlas, Bachmann or Kato couplers.

Truck and coupler are one single filament printed part. The couplers engage with a gentle push, to uncouple, "gods own hand" has to intervene. This replacement truck is made in several shaft lengths, space between the cars is trimmed to a minumum.

[bbussey]

I definitely wouldn’t convert back to truck-mounted couplers from body mounted-couplers.

Just drill and tap a new hole at the back of the coupler pad for a #00-90 screw and remount the existing 1015 coupler.

[u18b]

please show a video of two cars going around a curve.

 

[Albert in N]

Someone, in a prior post several years ago, suggested changing the body-mounted MTL couplers to Z MTL #905s.  So far this has worked, even on my 11-inch radius Unitrack curves, though they like the wider radius outer track loop better.  Not the best photos, but here they are:  [straight track]

[11-inch radius curved track]

[altohorn25]

Someone, in a prior post several years ago, suggested changing the body-mounted MTL couplers to Z MTL #905s.  So far this has worked, even on my 11-inch radius Unitrack curves, though they like the wider radius outer track loop better.  Not the best photos, but here they are:  [straight track]

[11-inch radius curved track]

I do this with all my MT heavyweights (swap out the couplers with body mounted Z scale 905's).

[Scottl]

I like the coupler design.  With some cosmetic refinement, that would serve on unit trains where you rarely uncouple.   

[peteski]

I like the coupler design.  With some cosmetic refinement, that would serve on unit trains where you rarely uncouple.

With such a long coupler shank which can't swing sideways (solidly attached to the truck) I wonder how it will work going over S-curves)?  Seems that more and more modelers and even manufacturers are converting their models to body-mount couplers.

[InterurbanModels]

Let the pictures speak. First video shows the raw trucks, second a mixed consist of a 1/ Life-Like E6a with home made truck mounted coupler 2/ Kato smooth sided coach (unmodified) 3/ MTL dining car with truck mounted couplers 4/ MTL HW coach with truck mounted couplers 5/ Railsmith MoPac coach (unmodified). Push and pull. Track is Kato Unitrack crossover. Distance is trimmed to the minimum that goes seamlessly through Kato superelevated R282 mm (R11'') curves.

[bbussey]

MTL Heavyweights are by any means beautiful cars. They nevertheless have two problems, which are also linked: 1/ an awful wide gap between the cars when coupled 2/ problems when running with truck mounted couplers on Kato/Rapido/etc cars.

MTL mounted the couplers out farther than they should have so that people could run the cars on radii that they shouldn’t. The solutions to the above are:

• Drill/tap #00-90 holes at the back of the mounting pad and reseat the coupler.
• Don’t run them with equipment with truck-mounted couplers.
• Don’t run them on less than 16” radii trackage.

Note that absolutely no one is clamoring for motive power to go back to the truck-mounted coupler designs of nearly half a century ago. Everyone is dealing just fine with long-wheelbase body-mounted-couplers motive power.

[InterurbanModels]

Drill/tap #00-90 holes at the back of the mounting pad and reseat the coupler.[/li][/list]

Of course I tried it out, to the extreme limit. To my deception, that only halved the gap from 6 mm down to 3. And then those cars start to tangle on S-curves.

I fully understand those who stand with body mount couplers, finally that's how the prototype works. But my rolling stock has to be "Unitrack-proof", like it or not.

The ideal solution : body mount couplers with elongation kinetics, as on commercial European N scale rolling stock (when the coupler swings, the gap between cars widens). But those mecanism are difficult to place in existing MTL floors without a lot of "butchery"...

[NorsemanJack]

Thanks!  You, my friend, are our new hero (it may take some time for everybody to realize this).  Why hasn't MT hired you on yet?  Hopefully whoever came up with the current design was shown the door long ago.

[peteski]

The ideal solution : body mount couplers with elongation kinetics, as on commercial European N scale rolling stock (when the coupler swings, the gap between cars widens). But those mecanism are difficult to place in existing MTL floors without a lot of "butchery"...

Yes, many European prototype models (even the short 2-axle freight cars) use the Kinematic coupler design.  It has also been used on some American models. One example is the FVM's  Hiawatha passenger train where the MTL couplers are mounted on a Kinematic arm.  Kato also offers Kinematic drawbar retrofit kit for their SP Morning daylight passenger set for close coupling.

[Albert in N]

   InterurbanModels, thanks since your design works as shown in your demo.  Also, shortening the gap with MTL stock body mount couplers is not as easy as some think; as your "butchery" photo shows.  Frankly, the Z scale 905s are not ideal.  Some twenty years ago, I bought this ancient ConCor set of Made-in-Italy Rivarossi standard Santa Fe cars.  They are keepers.  Although they lack some detail, their metal wheels and close coupling (even with Rapidos) make them shine!  They roll as well as my Kato streamlines (which also are close coupled).   Both roll much better than my MTL standard cars.

[bbussey]

Of course I tried it out, to the extreme limit. To my deception, that only halved the gap from 6 mm down to 3. And then those cars start to tangle on S-curves.

Only if the radius is too small. 

Alternate solution — don’t run long cars on tight radii.

[wazzou]

Only if the radius is too small. 

Alternate solution — don’t run long cars on tight radii.

Bryan, certainly you know that not everyone has the space or resources to build layouts to the same standard as you or others who attempt to do so with a high fidelity to prototype track dimensions.
I commend someone who has sought solutions to improve the appearance of model trains running on tight radius smaller layouts.
To suggest that because they have limitations with space, track radius and resources, they should only operate 44T locomotives pulling 40’ boxcars isn’t a good look.