Other options are:
Empire Express - Which I would probably use if I had to pay for new software today. I used their older trial version years ago and loved it. It was very simple to use but was accurate. I don't know how it compares now, but from the looks of it they just updated it to work on a modern version of MacOS.
XTrkCAD - It's free and open source. I tried it and was able to do a couple things in it, but it was unstable and had a steep learning curve. That was a few years ago and it has been updated a few times since. Being free it would be a good place to start.
Now what I did was I ran SCARM on my Mac using PlayOnMac. But this was before SCARM left beta, so it was still free and unlimited in what it could do. I couldn't do 3D view, but I was fine with that as I didn't need it for my layout design. You should still be able to do it this way with the current version of SCARM unless they have changed some of the core coding.
Of course if you use Boot Camp or one of the many Virtual Machine software packages to run Windows on your Mac (Which it sounds like you don't. But I'm including it for completeness.) you can run any Windows compatible rail software that way. But jut having a Mac doesn't mean you have options as I have listed some native MacOS things you can do above.