I am in the process of replacing the wheels on all my cars with metal wheels. I have bought cars with metal wheels and really like the sound and the ease of rolling. My question is what size wheel goes on what car. Our the sizes below correct for the type of car?
Covered hoppers–36"
Boxcars, Cement hoppers, gondola’s -33"
Autoracks, intermodal cars, coal hoppers – 25"
what about general use flatcars, tankcars, cabooses, Any help would be great. I am using intermoutain wheels to replace plastic wheels.
rswain: I think it depends on the era of the car and the capacity of the car. Are we speaking of HO or some other scale? Today’s covered hoppers would likely use the 36" wheel as would any other heavy high capacity car. A covered hopper from 40 years ago may have used a 33" wheel. I believe the autoracks and intermodal cars may use a 28" wheel, haven’t heard of the 25". Others will likely have more information on this.
The length or age of the car has nothing to do with what wheels it has. It is the load limit it must carry. Cars up to 77 tons ride on 33" wheels(it’s really the size of the axle bearings that are the important part). Cars over 77 tons ride up to 125 ton capacity ride on 36" wheels, and over that usually have 38" wheels. The reason the diameter of the wheel gets larger is the ‘contact patch’(where the rail meets the rail). A larger diameter wheel results in a larger ‘contact patch’. 26-28" wheels are used for total height above the rail clearance reasons. Cars like auto racks and intermodal flats will have these small wheels. The load carried by them is many times only 40-50 tons.
100+ ton capacity covered hoppers(like grain service) will use 36" wheels
Most box cars have a 50-70 ton capacity and will use 33" wheels
Cement hoppers(older 50’s era) were 70 ton capacity - 33" wheels
Cement hoppers(newer/current) have a 100 ton capacity - 36" wheels
Gondola’s can vary. Older 70 ton have 33" wheels.
Some newer gondolas have 100 ton capacity and will use 36" wheels
Auto Racks/Intermodal Flat Cars - 26-28" wheels
Double Stack cars - vary with load capacity.
Modern 100+ ton capacity coal hoppers - 36" wheels.
Older ‘twin bay’ coal hoppers(50-55 ton capacity) - 33" wheels
The key here is to look at the ‘capy’ stencil on the car - It will give you a clue aboout what kind of wheels/trucks are used.
Leaving intermodal cars, autoracks and piggyback flats out of the discussion initially, a good guide to the wheel diameter is the capacity line shown on the side of the car. (I think that sometime recently they started to not require this info on the car, but I’m sure that I’ll soon be corrected). Anyway, if it is a “70 ton” car or a normal boxcar, it will have 33 inch diameter wheels.
If it is a 70 ton covered or open hopper, it will have 33 inch wheels. 100 ton hoppers get 36 inch wheels. I believe that the new 120/125 ton hoppers get 38 inch wheels…
The modern tank cars get 36 inch wheels.
Most of the flat cars you are likely to acquire get 33 inch wheels. There are some depressed center flat cars the should have 28 inch wheels, but the kits have 33 inch.
There are a lot of variations amongst the intermodal stuff, and I don’t feel qualified to go into them lest I lead you astray.
Unless you are a stickler for prototype accuracy, the easiest thing to do is replace the wheels that came with the model with wheels of the same diameter. That way if the manufacturer did a good job with the coupler height, you won’t change anything by putting wheels on of a different diameter.
The only other thing to remember is that for the modern era you want to use wheels with a flat back, not the ribbed back that was prevalent on cars of an earlier vintage.
EDIT: sorry for the duplicate post. I just don’t type fast enough.
I’m glad you asked the question because I’ve been wondering the same thing. Also, nothing was said about tank cars, but I guess the same weight standard applies. since I model pre-1960, it seems that most of mine would be 33 inch wheels.