I've begun replacing my plastic wheelsets with Intermountain metal ones, and am now wondering which size to use, 33 or 36 inch? Obviously I can just replace the 33's with 33's, but it seems a lot of the most modern equipment has 36 inch wheels. Would one of you knowledeable people please explain to me what cars use what size wheels be they 28's, 33's, 36's or whatever. I know different sizes go with different trucks, so how does one verify which size to use? Have some of the older cars been upgraded with heavier duty trucks and wheels?? One last question, I just received the new Walthers National Steel Car 3 unit set (HO), and it has 33 inch wheels. Are the trucks and wheels correct? These cars look great by the way! Sorry for all the questions, but I'm a bit of a history buff, information sponge, and loony tune all rolled into one. Thanks in advance you guys! (and girls!)
I think most wheel sizes depend on how much the prototype wheel was supposed to carry. Most steam era cars will use 33 inch wheels which were rated for at least 55 tons. I think starting with 70 ton trucks you will want 36 inch wheels. ( not real sure on this) I know that with 100 ton trucks you will definately want 36 inch wheels. Of course most all passenger cars will use 36 inch wheels. Now a lot will depend on wheather youre trucks will allow you to use 36 inch wheels. A lot of manufactures still use 33 inch wheels in their trucks where 36 inchers would be more approiate. Mostly because the 36 inchers wont fit their trucks. I guess the best way to get the right size wheels is to compleatly change out the trucks to a better brand. I had to do this on my passenger cars since 36 inch wheels rubbed the brake detial on the stock trucks. Guess it all comes down to reasearching the car you want. Ther it is clear as mud .Mike
There are a couple of exceptions to that though. Auto racks and I think some doublestack cars have 28 inch wheels to lower the overall height of the cars.
Here's what I understand.... A good rule of thumb is that 70t trucks have 33", 100t have 36", and 125t have 38". The difficulty is working out what matches the prototype, for example some 86' boxcars are 70t rated and some are 100t.... Plus some things have 28", low deck autoracks, front runner's and (dependant on your era) Impack spine cars being some I know of. The good news is that the Walthers models of these prototypes (not the impack) come with metal 28" wheels anyhow.......(the "kit" walthers autorack is a standard deck height one and should have 33" ones) Articulated stack cars tend to get higher capacity trucks in the middle than the ends, so it's prototypical to have 33" on the outers and 38" on the joints, but the new Walthers car is drawbarred, so it would depend wether each deck is rated as 70t or 100t as to what I'd put under it. Better still, try & find a prototype! Not always easy I know. Having said all that I'm sure there are loads of exceptions to these ones. Hope that made sense!
I sent an e-mail to National Steel Car and they confirmed their 70 ton trucks use 33" wheels, 100 ton use 36", and 125 ton 38" wheels. They said the last cars they built for TTX used 70 ton trucks and had 169,400 lbs. load limits. My Walthers cars have a higher Load Limit (196,400lbs.) printed on them, and also have the number 110 painted near the trucks...SO NOW...my question is, did Walthers make a typo on the cars? Just flip the 96 to 69? Or did they model cars that in fact have 110 ton trucks, but only supplied 70 ton trucks with them? For crying out loud!! I'm going to post this in Intermodal too. One question makes another question, makes another question...
I've got a similar type of problem with Walthers 37' ore cars. The cars came with 33" wheels, but the isn't enough room for the trucks to properly swivel under the cars. In fact unless the car is pointed almost completely straight the wheels rub on the underside of the car. I've had to shim the trucks to get a little mmore clearance. I tried 28" wheels, which did indeed give me the clearance I needed, but then the trucks hang under the rails! I'm convinced that most manufacturers only make one or two trucks, and they put on the car whatever "looks" close enough. They spend lots o time on the cars, and little on the trucks. Maybe that's just my pessimism poking through, but the quality of manufacturing on the trucks just doesn't match up with the cars. Mark
Well it's official. I just got confirmation from National Steel Car. The Walthers cars have a typo. The load limits should read 169,400lbs, not 196,400 lbs.
