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Correct wheel size for freight & passenger cars

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  • Member since
    April, 2007
  • From: Boyne City, Michigan
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Correct wheel size for freight & passenger cars
Posted by navyman636 on Monday, August 12, 2019 10:20 PM

If someone can post general rules of thumb for the correct diameter of wheels for various types of rolling stock I'd really appreciate it.

Also, if anyone knows of a website that has good information about what types of trucks were used on which kinds of cars, I'd really appreciate that too.

Thanks, all!

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Posted by BNSF UP and others modeler on Monday, August 12, 2019 10:30 PM

I'm glad you posted this. I Have had the same question for a really long time but have kept forgetting to post it. Can I add a request for said rules of thumb for modern equipment?

BNSF: Big and Noisy but Surely Fascinating!

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Posted by navyman636 on Monday, August 12, 2019 10:45 PM

Sure can!  And I hope and trust we will both get some excellent directions from the experts here!

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Posted by doctorwayne on Tuesday, August 13, 2019 2:27 AM

I'm not sure about the very early days of railroading, but 33" wheels were pretty-much standard for freight cars from the early 1900s, and perhaps even earlier than that.  They were appropriate for cars up to a 70 ton capacity, but when 100 ton cars appeared, wheel sizes of 36" were mandated, and I believe that there are also 38" wheels in service.

Many passenger cars of the heavyweight era also used 36" wheels.

Some large modern cars designed to carry bulky, but comparatively light loads, such as automobiles, use 28" wheels to allow the cars to travel in areas where overhead clearances are low. 

As for truck types, there were many variations used over the years, some very similar-looking but with different features.  A railroad might choose trucks from an on-line customer, or a different type from elsewhere to suit a particular type of car or service.  There were high speed trucks that looked very similar to ordinary freight car trucks, and all sorts of features, some visible, others not so much, from different manufacturers. 

Fox trucks, like the one on the front of this plow...

...were an early type, but I can't find the date on which they would have been outlawed in interchange service.

Another very common truck was the built-up archbar type, as seen on this cinder gondola...

A built-up truck (multiple pieces bolted together) arch bar trucks were prohibited from interchange service after July 1, 1940.

I'm not sure when Andrews trucks first appeared, but they were in use during much of the same timeframe as the archbars, eventually superceding the archbars.  A popular feature of them was that they could re-use the journal boxes from the arch bar trucks.  The Andrews truck's sideframes were partially one-piece castings with some bolted-on parts.  Here's a pair under a ventilated boxcar...

Andrews trucks were banned from interchange in 1954, and that ban also included U-section Bettendorf trucks (one-piece cast sideframes) - also banned, in 1953, were Bettendorf T- and L-section trucks, also with one-piece cast sideframes.  These types appeared in the early '20s, so you can see that there was a broad array of types overlapping one another for many years.

Roller bearings first appeared on freight cars in 1923, and in relatively large numbers on passenger cars in 1926.  It wasn't until January 1, 1972, however, that all cars with journals 6 1/2"x11" or larger had to be equipped with roller bearings.
As modellers, we often classify solid bearing trucks with cast sideframes as "Bettendorfs, but Bettendorf was a foundry that produced many variations of the one-piece cast sideframes, as did many other manufacturers.

I believe that the trucks under this stock car are the T-section type mentioned above...

This car is equipped with National B-1 trucks, which were popular in the early '30s....

This one illustrates the generic "Bettendorf-type"...

...While this car is equipped with Dalman two-Level trucks...

I believe that these are Crown trucks, a type favoured by the Pennsy...

While I have a variety of trucks to show, here are some links to sites that will address this in more detail:

Freight Car Trucks 1900 to 1960

The Evolution of Freight Car Trucks

NMRA Data sheet

Freight Car Trucks: A Pictorial Comparison

Wayne

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Posted by gmpullman on Tuesday, August 13, 2019 4:27 AM

This is a handy reference:

http://mrr.trains.com/~/media/import/files/pdf/4/c/c/mr_pi_5-06_freightcartrucks.ashx

 At one time there was a free .pdf that had an overview of passenger trucks, extracted from the February, 2005 M-R but I don't see it on the site anymore.

Cheers, Ed

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Posted by navyman636 on Tuesday, August 13, 2019 10:19 AM

DoctorWayne, thank you for that amazing response.  It's awesome!  It's the sort of thing I print out and take to my shop to have as a reference.  It will get much use.

I also want to say a special thank-you to you.  In the past two weeks, after coming wihtin a hair's breadth of giving up on a lifelong dream of having my own layout, I finally resolved to just brush aside a lot of reasons for abandoning it and go ahead to build my dream.  I've been a Forum member for a long time, and I keep seeing your posts.  Like this one, a lot of those others have been printed as references because your information is so good, and your ability to communicate information is extraordinary.  It is people like you, so willing to share expertise and encourage the rest of us to believe we can do something we're unsure about, that make this hobby the wonderful, life-changing thing it is.

You're one of my heroes.  To get this response from you only demonstrates why.  I'm sure I'm not the only person who thinks this way of you.  Thank you again.  May you go from strength to strength!

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Posted by navyman636 on Tuesday, August 13, 2019 10:22 AM

Thank you, Ed!  I'll be reading this shortly!

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Posted by doctorwayne on Tuesday, August 13, 2019 2:37 PM

Thanks for your very kind words, navyman636.   There are a lot of helpful people on this and other forums, usually willing to jump in with assistance, especially if they're familiar with the subject under discussion.  This often attracts others seeking info on the same or related topics, and it encourages all of us, knowledgeable on the topic or not, to share what we know or learn from what's being discussed. 
To paraphrase The Most Interesting Man in the World, "Stay thirsty, my friends, for knowledge!"

Wayne

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Posted by riogrande5761 on Wednesday, August 14, 2019 6:23 AM

There is a saying: A word is worth a thousand pictures.  or something like that.  Clown

navyman636,

Mr. Wayne has given some detail about earlier practices, like 1950's and earlier, but if you are interested in more recent railroad practice, say the last 50 years, the general rule of thumb is 70 ton freight cars have 33 inch wheels and 100 ton 36 inch.

For some cars pushing the upper limits of height, such as auto racks, 28 inch wheels have been used to help reduce height.

Here are some links for further reading.

http://cs.trains.com/trn/f/111/t/83279.aspx

Rio Grande.  The Action Road  - Focus 1977-1983

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Posted by richhotrain on Wednesday, August 14, 2019 6:33 AM

To sum it up.

~ Passenger cars use 36" wheels

~ Freight cars generally use 33" wheels

Rich

Alton Junction

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Posted by riogrande5761 on Wednesday, August 14, 2019 6:40 AM

richhotrain

~ Freight cars generally use 33" wheels

Rich

Anymore, not so much.  There is a large percentage of freight cars in the 100 ton category so 36 inch wheels are very common.

One example: D&RGW's great steel fleet of quad hoppers were all 100 ton purchased between 1964 and 1982 by the thousands.  Tank cars largely have 36 inch wheels as well.

Rio Grande.  The Action Road  - Focus 1977-1983

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Posted by dti406 on Wednesday, August 14, 2019 10:40 AM

There are also cars that require 38" wheels for 125 Ton Loads, like the Clamshell Gons of the P&LE and B&LE, the NYC/P&LE Hot Coil Cars and many of the Multi-Unit Container Cars that have a combination of 38" and either 33" or 36" Wheels.

Rick Jesionowski

Rule 1: This is my railroad.

Rule 2: I make the rules.

Rule 3: Illuminating discussion of prototype history, equipment and operating practices is always welcome, but in the event of visitor-perceived anacronisms, detail descrepancies or operating errors, consult RULE 1!

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