Model Railroading > Wheel Sizes

Later this year i plan on changing all my plastic wheels out with metal ones. But I dont know which cars get 36 or 33. I know its based on the car weight but what is the max for 33? is there a chart or something to reference for the information?


And for extra info whats your opinion on who has better looking and/or rolling metal wheels?

Short answer...

gross tonnage of car...
<70 ton = 28" wheels
70-100 ton = 33" wheels
100-125 ton = 36" wheels
>125 ton = 38" wheels

This isn't a rule but a good start in the right direction. Lots of models even state within the data on the ends what size wheels they're supposed to roll with. I've probably got the math wrong to some degree, but... I often go by the "LD LMT" number on the side of a freight car (assuming the model manufacture puts accurate numbers on their car). Lets say you have a 3-bay grain hopper that has "LD LMT 221400", divide that number by 2000 and you essentially get 110.7 tons, well within the range for 36" wheels.



For metal wheel sets, I'd recommend either InterMountain or ExactRail all metal wheel sets. InterMountain also produces 38" metal wheel sets.

Mr. MRL - ready to be corrected...



Edited 2 time(s). Last edit at 07/29/13 20:32 by MrMRL.

MrMRL Wrote:
-------------------------------------------------------
> Short answer...
>
> gross tonnage of car...
> <70 ton = 28" wheels
> 70-100 ton = 33" wheels
> 100-125 ton = 36" wheels
> >125 ton = 38" wheels
>
> This isn't a rule but a good start in the right
> direction. Lots of models even state within the
> data on the ends what size wheels they're supposed
> to roll with. I've probably got the math wrong to
> some degree, but... I often go by the "LD LMT"
> number on the side of a freight car (assuming the
> model manufacture puts accurate numbers on their
> car). Lets say you have a 3-bay grain hopper that
> has "LD LMT 221400", divide that number by 2000
> and you essentially get 110.7 tons, well within
> the range for 36" wheels.
>
>
>
> For metal wheel sets, I'd recommend either
> InterMountain or ExactRail all metal wheel sets.
> InterMountain also produces 38" metal wheel
> sets.
>
> Mr. MRL - ready to be corrected...


Don't forget passenger rolling stock: 36" wheels.

You didn't state the era you model. A GENERAL rule of thumb is that the 40' and 50' cars from the "classic era" rode on 33 inch wheels. As car weights and capacities grew, so did the wheels. As cars moved up into the 90-100 ton range the 36" wheel was the appropriate size. So the modern covered hoppers and coal hauling cars are riding on 36".

I used to go by era but there are plenty of modern cars that ride on 33" wheels as well. Some are due to car height. Tri-level auto-racks for example roll on 28" wheels to make them a bit shorter. Modern Maxi-IV cars have 36" wheels at the couplers and 38" wheels at the spines. Some cars are odd like that.

Overall though you can do research on the web and find photos of the cars you have. Usually the wheel size is stenciled on the car ends. If it isn't, you can visually see the difference in size between 33" and 36" though when in doubt go 33".

This website is a great resource for photos as is Railpictures.net, Railroad Picture Archives, Fallen Flag Railroad Photos, and others.

Lee Ryan - Rio Grande Fan
Denver, CO

swsf Wrote:
-------------------------------------------------------
> The simplest method would be to match the wheel
> size already installed on the model. If it has 33"
> plastic wheels, replace them with 33" metal
> wheels. If you install a different size wheel than
> what came with the car, the coupler height may be
> affected and may not line up as well. This assumes
> that the model was designed for a specific wheel
> size and the couplers were positioned for those
> wheels.

This is good advise I converted several yrs ago I had a number of old roundhouse modern tank car kits that prototypical should of had 36" wheels but when I changed over 2 things happened coupler height and clearance I found wheels rubbing the frame in curves. So I swapped out the 36 of 33", sometimes we sacrifice proto for operation.

Im doing modern era

Posted from Android

stacktrain Wrote:
-------------------------------------------------------
> Later this year i plan on changing all my plastic
> wheels out with metal ones. But I dont know which
> cars get 36 or 33. I know its based on the car
> weight but what is the max for 33? is there a
> chart or something to reference for the
> information?
>
>
> And for extra info whats your opinion on who has
> better looking and/or rolling metal wheels?

Thanks for asking the question, I plan to start upgrading my cars this fall and was thinking the same thing.

Nathan

Articulated cars have two differnt wheel sizes because they use 2 differnt trucks. The trucks at the couplers are 70ton they use 36 inch wheels. The trucks under the artuculation are 100ton they use 38 inch wheels.

Posted from Android

So articulated Autoracks have 38 inch wheels

stacktrain Wrote:
-------------------------------------------------------
> So articulated Autoracks have 38 inch wheels

I don't think so. Autoracks have relatively light axle-loading. I'd be surprised if their wheels are larger than 33". But I must concede I haven't paid any attention to articulated autoracks -- unlike articulated stack cars -- because they're too modern for my interest.

I ment articulated stacks in my post. I've noiced the articulated racks have 28s but not sure if the middle truck is 28s or not. May have to research umler and see.

Posted from Android