Model Railroading > Too Much Realism!

While running my layout a car derailed and caught on some scenery, and the resulting slack run-out broke a knuckle.
Really.
The first photo is exactly as I found the car (Genisis) and the knuckle on the walkway to the left. 
I was able to poke the iPhone into the bridge truss and take this picture before I touched anything.
If it had fallen to the floor (the bridge is a duck-under) I'd have never found it and never figured out what happened.
You can see that the un-coupling arm/pivot shaft is still in place on the end of the car.
When I got it to the work bench and examined it, I could see that the pivot hole on the rear of the (plastic) knuckle had been split. 
It is asking a lot of my iPhone camera but if you look closely you can see some white background through the crack at about the 6 o'clock position.
You cannot make this stuff up..... I really did break a knuckle.
Of course the replacement coupler is a trusty Kadee.
Just like the prototype, the delay to this train held up another plus a Sperry Rail Detector, just like a day at work.
 



Edited 2 time(s). Last edit at 11/19/20 21:35 by railstiesballast.

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Thanks for sharing. Yup, a metal Kadee is your best replacement. Most of us have had bad luck with plasic knock-offs, especially with longer trains.

Victor A. Baird
http://www.erstwhilepublications.com

That bridge is some fine modeling.

So maybe be a bit more gentle with the throttle?

This is awesome.  Love it!  I'll make a post about a similar 'real life' incident on the layout that we had to handle as part of things too.  Love when this stuff happens - as you said, just like the real thing.

~RGDave
https://onondagacutoff.blogspot.com/

Great detailed modeling. I just replaced the last plastic couplers with trusty metal Kadees on my car fleet. Had something interesting happen on my layout many years ago. Seems a boxcar derailed and the train seperated, I stopped the train before it created a mess. Found that the rear wheelset had come out of the truck and was laying in the gauge. (Can't find the picture) Seems the old metal springs in the Athearn truck (HO) had gotten weak and allowed the sideframes to spread.
CR

That there is one of countless reason some toss their clone and install Kadee from the get go. Of course if ultra realism is important leave the plastic clones on. ;-)

Posted from Android



Edited 1 time(s). Last edit at 11/23/20 05:10 by SPDRGWfan.

I wonder if the plastic Athearn/ McHenry coupler might be closer to scale in terms of forces it can withstand, versus the metal kadee couplers. In reality, a type E coupler knuckle is not a solid hunk of metal, but is engineered with voids for a designed capacity of 350,000 #'s of force with a margin before it fails. The idea is to have the easily replaced knuckle be the weak link so it fails before more difficult to replace componets fail, but that doesn't always work out in practice. Of course a solid metal knuckle would handle a lot more force, but not so easily replaced. So I figured the scale force of a Type E coupler is 8.5 ounces (using 87^3), which seems about right for a plastic knuckle. The Kadee coupler can handle forces far beyond it prototype capacity.
I also use the 87^3 for figuring what the scale weight of cars should be. For instance a empty car of 60,000#'s would have a scale weight of 1.46 ounces. A 263,000# car would be 6.39 ounces. And a 286,000# car would be 6.95 ounces.  A 60' HO scale car should weight a little over 5 ounces by NMRA standards, so it's close to the scale loaded weight. But a 1.5 ounce "empty" car would be very light in HO scale, and prone to derailments and stringlining. Gives one a better apperciation of prototype engineers train handling skills and challenges.

Ted Curphey
Ontario, OR

Am in several scales and have been into model RR most of my life and started using Kadees way back in the 50s.  Had a lapse of HO for several years and came back into it about six years ago. Got quite a few cars and engines some of which had plastic couplers on them which were nothing but trouble knuckles would open  for no reason, too soft plastic. Also a few years back some one started making them in 1 1/2 inch scale, looked great were less expesive than metal ones wow what a deal. Well when pulling a dozen cars or passenger cars holding three people with about five loaded they would some times open. Not a good deal in any way plastic can be good or bad but in large scale can be a hazard due to weight as a loaded passenger train with six cars, conductor and engineer cars two units on the point can weigh in at well over 6000 lb. Boyd in Chiloquin OR home of Train Mountain RR.

Even in real life those plastic knuckle pins snap. Replaced many with real steel ones.

A good brakeman will kick the old knuckle over the edge of that bridge and into the crick, so the trainmaster or road foreman would never find it.

Dave in MT

One thing we modelers can't scale is air brakes.  Breaking a train in half full scale is definitely a problem, but it an be a severe problem in HO scale depending on the train length, weight of cars, rolling friction, etc.  A long time ago, our club set standards for our layout, including Kadee metal couplers, NMRA standards for car weights, metal wheels, etc.  Using those standards, we can pull 40-car trains up a very long 2% grade without coupler failures, string-lining, etc.  But.............we have had occasions where a member cheats or simply failed to inspect a car with plastic couplers or has a bunch of lead sleds on the rear of the train and light cars on the front end.  I think we've had a couple string-lines and several cases where plastic couplers failed or, for some reason, an uncoupling occurred.  A long, heavy, nicely rolling train with no brakes will naturally descend the grade at an ever increasing speed.  We have had a few exciting events where a 90 mph freight train makes the descent, caboose in the lead.  Very much a reminder of the amusement park roller coaster.  And there is always someone who is tempted to add a few more cars to his train to see what his locomotive will do on the grade.  We have considered putting a mini-dumpster at the bottom curve on the grade.



Edited 1 time(s). Last edit at 11/20/20 10:18 by jdw3460.

PHall Wrote:
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> So maybe be a bit more gentle with the throttle?

He doesn't have the benefit of air to help him with train handling.

I have two percent grades and I find that any train over about fifteen cars lengths and those McHenery's are prone to fail. Mine get Kadee 158s soon as they leave the box now. 

Great photo Mike!

Thanks for the photo and what happened.  Very entertaining.

The ultimate realism would be a decoder that makes the sound of the air dumping when the train comes apart.

TAW

Dang - modeling is getting TOO realistic!

Happens to us all. If you want to be more realistic, leave the knuckle on the ballast all year till the next UC Gang shows up. 😆

Posted from Android

PHall Wrote:
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> So maybe be a bit more gentle with the throttle?

That's what the real railroads say to real engineers. So this is totally prototypical. 

Except for that bright metal, granular surface you see on a real broken knuckle. 

Thanks, guys for all the comments, this was fun.
The train was going about 15 MPH at the time, a car toward the rear of the 13-car train derailed and hung up on a cut embankment. not a heavy drawbar effort until 12 axles met a stopped car.

Exactly why the San Diego La Mesa club doesn't allow plastic couplers. You wouldn't want that happening at Cliff or anywhere on the climb out of Caliente...