The Home Machinist!

I'll second the notion that you should choose the locomotive design which calls to you. That's important. I didn't . . as a teenager I was propagandized by our then club president (and I wasn't the only one) to build what he thought I should build, in the scale he wanted everyone to be in. I never finished the loco and never will, but it wasn't a complete waste . . I learned a lot about what NOT to do, and I learned not allow anyone tell me what I ort or ort not build!

And rubber tires are still a bad idea, otherwise everyone would be burning them!

I started at age 20 years old. I am now a senior. I was in love with the Southern Railroad and I decided to go for the gold. I built a Southern Ps4. I spent nine years at 30 hours a week on my engine. I do not recommend a major project of magnitude on the first engine, but why not.
Build that engine that is your passion and you will love every minute just as I did!! Now I am building a N&W canteen to pull behind her. Who knows, I may just paint it green and put a Southern on it.