Re: UP HK-50-3 Ballast Hopper


rdgbuff56
 

Some 100 ton coal hoppers have wheelsets that extend further than ends.

Francis a. Pehowic, Jr.

On Wednesday, January 26, 2022, 04:41:21 PM EST, Dennis Storzek <dennis@...> wrote:


On Tue, Jan 25, 2022 at 02:31 PM, Allen Montgomery wrote:
The second picture shows the amount of overhang of the wheel sets as I had to move them out to gain some room for the trucks to pivot. That was the one thing I had to change from the drawing in Terry Metcalfe's book.
I don't know exactly how to broach this subject without hurting feelings, but with 3D printers leading a lot more people to try to design model railroad equipment, it needs to be discussed. While the printed body looks really fine, the misplaced trucks make it look like an ore car. Those of us who have done this work know that until everybody migrates to P:87, there are going to have to be compromises made, and choosing the right compromise is part of the art.

First off, identify the proper trucks to design for. If those are 100 ton trucks with 36" wheels, they are seven inches longer than the proper trucks; 4" in the wheelbase, and 3" more in the extra diameter of the wheels. Here is a link to an older version of the same design car: CBQ220145

Note the relationship of the trucks to the features on the body; The wheels don't extend past the end sill, few prototypes do (only ore cars) and the truck bolster is back under the full height side sheet, since that's where the body bolster, that transfers the weight of the car to the truck, is located. This relationship is the same on all hopper cars, with very few exceptions.

Even with the proper trucks on this car, however, there are likely to be problems. Our commonly used wheels, even the Code 88 wheels, have deeper flanges than the prototype, so the truck is still about two or three inches too long, In addition, we expect our models to go around curves that would derail the prototype. This is where the designer needs to get creative. My suggestion would be to put the truck king pin where it belongs, then shorten the discharge gate by whatever is needed to gain adequate truck swing. There is no real visual "landmark" on the body above the end frame of the discharge chute, so there will be nothing that looks wrong, and the slight variation from the prototype will never be noticed.

Dennis Storzek

Join main@RealSTMFC.groups.io to automatically receive all group messages.