For years, growing up in a hobby shop and as a modeler, I always called these safety appliances "grab irons". It wasn't until I started working at the Grand Canyon Railway, and had my first interactions with the ATSF and regulatory agencies, that I found that they are referred to as "hand holds" and that is how they are referenced in Part 231 (Regulation).
With that said, the Safety Appliance Act (Law) references both "hand holds"
or "grab irons". Maybe something in the translation over the years, but thought that the terminology difference was interesting.
MD Ramsey