Freight Car Wheel Size

[6axlepwr]

I am not all that experienced with freight cars. So I want to ask a question about wheel size.

I am using Fox Valley wheels. I bought a bulk pack of 36" wheels. Looking through my stash of parts, I came across a package I had purchased a few years ago that are 33" wheels. 

So I have to ask. How do I know what is the correct wheel size to use for a particular freight car?

I know autoracks and some 89' flats use 28" wheels. Nobody offers 28" wheels though. I was wrong. FVM offers 28" wheels. So for the 33" and 36" wheels, is there a specific type a car that uses a particular size? Or is 33" wheels for older era cars and 36' for new modern and rebuilt cars?

[tehachapifan]

It would be great if a comprehensive list was developed. That said, I believe most modern tank cars and covered hopper cars have 36" wheels due to their weight. I also understand many articulated well cars even have 38" wheels at the articulations between cars and 33" wheels at the ends.

...I also understand, as a general rule, 33" wheels ride on 70 ton trucks which often have 2 outwardly-visible springs and the 36" wheels ride on 100 ton trucks which often have 3 outwardly-visible springs.

[reinhardtjh]

Check your friendly neighborhood "Best of the Wire Archives" - What wheels on which car?

[6axlepwr]

Check your friendly neighborhood "Best of the Wire Archives" - What wheels on which car?

That is a good one for discussing autoracks, but I want to know in general. Russ's general rule seems pretty good, but I do want to know more though to be better educated one what is the appropriate size wheel to use.

[craigolio1]

Passenger cars get 36" wheels too.

Craig

[w neal]

Wasn't there some rule about combined car weight limts (capy + load limit?) being under 162,000 then 33" wheels, otherwise 36" over that weight limit? Have to look at my notes at home.

Modern coal hoppers and 50' high cube cars (heavy paper rolls) are 36" I think.

[nsbob]

33in up to 77t
 36in 78-100t
 38in above 100t

1) 70 ton trucks w/ 33" wheels
 2) 100 ton trucks w/ 33" wheels
 3) 100 ton trucks w/36" wheels
 4) 125 ton trucks w/ 38" wheels

1) 140,000 to 150,000 load weight
 2) 165,000 to 175,000 load weight
 3) 190,000 to 205,000 load weight
 4) 220,000 to 230,000 load weight

28" wheels on most tri-level autoracks.  38" wheels are common to newer articulated double stack cars, the cars are labeled 125T, they're also used on Flexi-flo covered hopper cars.

Here is a good start.  I found this on the Model Railroad Hobbist website at mrhmag.com from Josh at http://rr.blockchoice.com.

[jpwisc]

If only it where that simple. I took some measurements a while ago of some FVM metal wheels and compared them to some prototype measurements I took. The non-prototypical flange sizes can add another side to the argument. I wrote about this last year on my blog, you can see it at:
http://ambersub.blogspot.com/2013/05/wheel-dilemma.html

[Kisatchie]

You might be interested in this - Micro-Trains Barber trucks come with 33 inch wheels, but Micro-Trains often uses them as if they were 100 ton trucks. I wouldn't try putting 36" wheels in the Barber trucks, because it'll change the coupler height on the car, and the flanges might scrape on the underframe.


Hmm... "flanges." That
word always sounds funny
to me...

[jagged ben]

It would be great if a comprehensive list was developed. That said, I believe most modern tank cars and covered hopper cars have 36" wheels due to their weight. I also understand many articulated well cars even have 38" wheels at the articulations between cars and 33" wheels at the ends.

...I also understand, as a general rule, 33" wheels ride on 70 ton trucks which often have 2 outwardly-visible springs and the 36" wheels ride on 100 ton trucks which often have 3 outwardly-visible springs.

100-ton trucks always have 3 outward springs, AFAIK.  70-ton trucks may have 2 or 3.  The two different MT roller bearing trucks are both actually 70-ton.

The 38" wheels on articulated well-cars belong to 125-ton trucks.  Only Kato makes this in N scale.