OGR causes OCD

[Tom Dempsey]

I don't think so Roy, metallurgy has made some progress since 1938. The couplers take more abuse than anything else on a railcar, and while quite rugged, those breakages do happen. Not really all that often all things considered. It's the knuckle pin that is most likely to be broken when walking a cut in the yard. I probably saw a hundred broken coupler pins for anything else on the coupler broken, and even that was an event that while not necessarily unusual, certainly didn't happen every day.

[robert.]

When i was a kid i grow up 300 yards from Doylestown's train station. At that time they still had freight. The engineer would ram cars into place. He would take a run at cars and whack shoot them like pool balls onto a siding. As a kid i had no clue about metals and strength. i can't believe nothing ever broke for him. My father was so worried i'd do that with toy trains. When he hit them they would roll 300-400 yards.

[Chris Rock]

Interesting. I've been running 30+ car trains with Kadee plastic couplers up and down 3 percent grades for 15 years now without a failure. I've had an Atlas coupler failure in that time. Not a bad record.

I don't think the person who wrote the article knows what he is talking about.

[ScaleCraft]

Wait until you run them outdoors in all weather (not so stored).
Those trip pins rust. You're crawling down a long 4%, the cars bunch up, which pushed the jaws open....and then you reach the bottom and pull away..and leave a significant portion of the train...and you cannot couple...and 0-5-0 the car into the shop...and use an oiler, then manually operate the jaw for 20 minutes and cannot get it to close by itself....and you rip them off and put something else in place thereof.
Theorems and Postulates. Remember that.

[Rufus T. Firefly]

Wait until you run them outdoors in all weather (not so stored).
Those trip pins rust. You're crawling down a long 4%, the cars bunch up, which pushed the jaws open....and then you reach the bottom and pull away..and leave a significant portion of the train...and you cannot couple...and 0-5-0 the car into the shop...and use an oiler, then manually operate the jaw for 20 minutes and cannot get it to close by itself....and you rip them off and put something else in place thereof.
Theorems and Postulates. Remember that.

Ok, so what do you use?

[ScaleCraft]

Depends. In Half-zero, DeVore, dummy, mostly Mantua. Zero, Monarch, ScaleModels (preferred). In LS, preferred is Lionel LS knuckles, but Delton has identical heads (because Schuster designed Delton and Lionel), followed by modified Botchman.

[Chris Rock]

Wait until you run them outdoors in all weather (not so stored).

I will be waiting for that forever, as will most people.

For those who run outdoors, good information. For the rest of us in the majority, plastic Kadees work just fine, 10, 20, 30 cars.

[ScaleCraft]

Wait until you run them outdoors in all weather (not so stored).

I will be waiting for that forever, as will most people.

For those who run outdoors, good information. For the rest of us in the majority, plastic Kadees work just fine, 10, 20, 30 cars.

And you're not reading earlier posts. Breakage. At inopportune times.
Theorems and Postulates.

You can have any number of examples to prove they never fail, but it only takes one to sink the idea they never break.

[Chris Rock]

Duh! Percentage of risk we all take by running something mechanical and that applies to everything and not just couplers. I have 0 failures for Kadees running indoors for 15 years. Easy calculation. Bottom line, the notion that plastic Kadees will only be able to pull 4 cars is a big old pile of bunk.

[ScaleCraft]

Duh! Percentage of risk we all take by running something mechanical and that applies to everything and not just couplers. I have 0 failures for Kadees running indoors for 15 years. Easy calculation. Bottom line, the notion that plastic Kadees will only be able to pull 4 cars is a big old pile of bunk.

Oh, I agree. But we have morphed into breakage period.
BTW, on roadbed that moves, as in up and down, depending on settling and/or frost heaves, long cars with smaller head #1 body mount couplers, they won't stay coupled. Which is why 100% of my rolling stock is talgo mount. And we regularly pull 28-34 loads up 150' of 4% with them.

[MurphOnMillerAve]

With the snow, I'm wondering if blue brittleness may be a factor. Similar to the Liberty ships that broke apart in colder areas of the North Atlantic.

What? Please consider telling us about that.

[Roy]

With the snow, I'm wondering if blue brittleness may be a factor. Similar to the Liberty ships that broke apart in colder areas of the North Atlantic.

What? Please consider telling us about that.

Essentially, steel changes from ductile to brittle at lower temperatures.

This explains it better: https://en.wikipedia.org/wiki/Liberty_ship

Scroll down to Problems - Hull Cracks.

[MurphOnMillerAve]

Very interesting, Roy, Thank you. I had no idea of any of that.

[webenda]

Essentially, steel changes from ductile to brittle at lower temperatures.

Roy causes OCD also. Here I go again...

The first railroads to learn if "Cold Embrittlement" of steel were those built in Canada and Siberia.
The problem was not noticed in the USA until the winter of 1910-1911. (Relying on my memory here, I learned this in Metallurgy 101 36 years ago.)

Annual Report
By New York (State). Public Service Commission. 2nd district
Sixth Annual Report, for Year 1912
Page 54 Public Service Commission, Second District
11. Rail failures in winter are excessive as compared with summer. In New York state the principal kinds of rail failures for three years averaged about 200 per month for nine months and varied from 364 to 895 per month for the remaining months of January, February, and March. this variation was apparently caused by variations in the severity of the winters.

The problem has not been solved.

Cite as
International Journal of Minerals, Metallurgy, and Materials
May 2012, Volume 19, Issue 5, pp 409–420
Brittle fracture occurs frequently in rails and thermite welded joints, which intimidates the security and reliability of railway service. Railways in cold regions, such as Qinghai-Tibet Railway, make the problem of brittle fracture in rails even worse. A series of tests such as uniaxial tensile tests, Charpy impact tests, and three-point bending tests were carried out at low temperature to investigate the mechanical properties and fracture toughness of U71Mn and U75V rail steels and their thermite welds.

I can hardly believe we cannot even figure out why it happens and fix the problem.

WHY?
The answer, in the words of Jianming Huang, who wrote a PhD thesis entitled: "Ductile-to-Brittle Transition in Body Centered Cubic Metals..." in 2004 1), is: "The (..) mechanism of this (ductile to brittle) transition still remains unclear despite of large efforts made in experimental and theoretical investigation.”
© H. Föll (Iron, Steel and Swords script)

Chart of steel embrittlement temperatures:

brittle_ductile_transition.gif (19.75 KiB) Viewed 6660 times

So, if you go into battle with a sword in a really cold climate you better warm that sword up before you have to use it.

Ductile to Brittle Transition or Cold Shortness
Some Observations
Cold shortness was a big problem for a long time in sword making. It means that things get brittle when it's cold. The word "short" is old English, meaning "having a tendency to break or crumble" as in shortcake or shortening. It doesn't mean that things get smaller when it's cold. Nowadays we call the more general effect that properties change from ductile to brittle with decreasing temperature "ductile to brittle transition" or DBT.

If a ductile-to-brittle transition occurs in your material, you have a serious problem. If your material is under some mechanical load, it might simply break, often suddenly and without any warning. Major disasters we know about were caused by this. Most certainly there were also a lot of minor disasters we don't know about, for example when some warrior's sword suddenly broke because it became too cold for its Temperature of Ductile to Brittle Transition or TDBT.

The transition can be rather sharp. At 20 C (68 F) you may have a ductile phosphorous steel sword that is hard to break. But around freezing (0 C (38 F)) it will snap at the slightest impact since the fracture energy is now roughly 100 times smaller.

[MurphOnMillerAve]

.....If a ductile-to-brittle transition occurs in your material, you have a serious problem. If your material is under some mechanical load, it might simply break, often suddenly and without any warning. Major disasters we know about were caused by this. Most certainly there were also a lot of minor disasters we don't know about, for example when some warrior's sword suddenly broke because it became too cold for its Temperature of Ductile to Brittle Transition or TDBT.

The transition can be rather sharp. At 20 C (68 F) you may have a ductile phosphorous steel sword that is hard to break. But around freezing (0 C (38 F)) it will snap at the slightest impact since the fracture energy is now roughly 100 times smaller.

Do you suppose this factor may have been contributory to the Titanic breaking in-two while sinking, since it had been traveling in ice-cold waters; perhaps, even part of why the ship's iron side could not do damage to the iceberg rather than having the ice critically damage the ship?