Maybe they should be called “draft gear,” but they don’t look much like them, and they don’t behave much like them, and so, like “throwbars” they should get their own name. “Coupler box” is what I’ve always called them.
I standardized on Accumate couplers for a couple of reasons: firstly because they are near-scale size, and secondly because Sergent Engineering couplers will fit the coupler boxes. I played around briefly with Sergent’s couplers, and I wasn’t happy enough with my ability to manipulate them at the time; however, I’d like to have the flexibility to go back and try them again one day.
I keep having to go back and measure the coupler boxes every time I design a model. How thick are the components, and how high do you have to make the mounting pad so they will be the right height? For 622, I want to incorporate the box right into the design of the pilot and tender end beam. So, I needed to draw the whole boxes.
To facilitate future modelling, I have created a 3D model just for the coupler box. If you’re an OnShape user, and I hope by now I’ve convinced some of you to try it, you can link to the latest version of the two parts and incorporate them into your own designs. Caveat emptor. I created the model by measuring, and it doesn’t account for draft angles or anything. The model parts are 2’10” above the origin; so, all you need to do is link to it, and it will be positioned correctly if your rails are level with the origin too. It should serve my purpose, I think, and maybe yours too.