I don't think there's a simple answer, and the 'intend to sell' part makes a big difference.
When a business sells models for profit, they can expect whoever owns the copyright, IPR, or trade-mark to want a cut! A business is also required to pay tax, ensure products are safe (toys are different from display models), satisfy consumer law, and a host of other complications.
So, decide if this a business or just a minor bit of below the radar private enterprise unlikely to attract attention. An example might help:
- A friend quietly paying for a copy of the Hogwarts Express for private display at home is unlikely to be a problem.
- The same engine used in a TV advert would attract attention. Someone would have to get permission and pay.
- Selling a trailer full of Hogwarts Express engines at a Xmas Market would probably result in a tap on the shoulder and worse.
- Selling hundreds of Hogwarts Express Models on the internet would result in spectacular legal fireworks!
The owners of the JK Rowling Franchise aggressively protect their ownership of the Hogwart's Express. I've no idea how Boeing or Hitachi would react, if at all, but I'm sure they would protect their interest if there was money in it.
Essential to avoid existing franchises. Copying current designs is riskier than modelling yesteryear. But I think the real trigger is the amount of money involved: up to a point no-one cares what we do, after which it gets more and more exciting with increasing value. A chap making a bob or two on the side in his shed is very different from a professional CNC shop churning stuff out 24×7. Which are you?
Dave
Edited By SillyOldDuffer on 03/12/2021 10:21:03