Wheel Size for freight cars


 Can anyone tell me why there are sets of wheels sold for freight cars in 33" and 36"?  Why are there two sizes?

Mountaingoatgreg's picture

Because the prototype does

Simple answer: Because the prototype has different size wheels. There are also 28" wheels for some intermodal equipment. As a side note most cars pre-1965 are 33" after that larger and heavier cars have 36" wheels. I hope this helps. One some modern cars the wheel size is indicated on the data on the end of the car. On some models this data is duplicated and can be used to decided which wheels to buy.

Be Wise Beware Be Safe

"Mountain Goat" Greg

Click the banner to see more on the SP&S Oregon Trunk


wp8thsub's picture

Re: Wheel Size for freight cars

Cars of 100-ton or so capacity will tend to have 36" wheels, while 70-ton and lower capacity cars will have 33".  There are exceptions, but you can use this as a general guide.

Rob Spangler  MRH Blog

Wheel sizes


Thanks for the info.  Does the 36" vs 33" have anything to do with age of equipment? Like late 1980's to mid 1990's?

David Cameron 

Wheel Sizes

 "Mountain Goat" Greg;

So cars running in the late 1980's to to Mid-1990's would have 36" wheels?


David Cameron 

wp8thsub's picture

Re: Wheel Sizes

"Does the 36" vs 33" have anything to do with age of equipment? Like late 1980's to mid 1990's?"

As was noted in another post above, the larger wheels started to become more common in the 60s, coinciding with the development of higher capacity cars (roughly over 70 tons).  You can realistically include them from the early-mid 60s on, maybe a bit before.

Rob Spangler  MRH Blog

cv_acr's picture

Size vs. Age

Wheel size has more to do with capacity of the equipment than its age.

As noted, trucks designed for 100-ton capacity cars will generally have 36" wheels.

70ton trucks generally have 33" wheels. This is basically your "standard", but in recent years most new cars are larger and heavier.

Modern autoracks have 28" wheels. Automobiles are relatively light, bulky cargo, plus the small wheels lowers the bottom of the car a bit.

33" and 36" wheels need to be used appropriately on specific cars, not just randomly based on their age.

nbrodar's picture

Let us not forget the 38"

Let us not forget the 38" wheels on the 246K cars now in service.


joef's picture

If someone wants to do an article

If someone wants to do an article for MRH illustrating the different wheel sizes and how to know when to use which - with prototype photos - that would be great.

An example of things to cover would be how do you know a 70-ton car from a 100-ton car? Can you tell just by looking at the trucks what sized wheels should be included?

The more "teaching a modeler to fish" rather than just "give them a fish" type insight you can provide, the better. Then modelers will feel much more confident about what wheel size goes where.

Joe Fugate
Publisher, Model Railroad Hobbyist magazine

Joe Fugate's HO Siskiyou Line

Mountaingoatgreg's picture

Me me I will..


I would be willing to write that article...I have access to car repair facilities, wheelsets, trucks, and FRA rulebooks to help supliment the article.

Be Wise Beware Be Safe

"Mountain Goat" Greg

Click the banner to see more on the SP&S Oregon Trunk


SteamDonkey74's picture

I look forward...

I look forward to reading such an article. I have been swapping like wheels for like when I replace N scale plastic wheels with metal wheels. It'd be nice to have more of an idea of why I am doing what I am doing.


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