Hello once again,
I first should tell you that I got my engine on the board on "Rule the Rail!." However, needing to finish detail by adding a chainlink on the front handrails, suddenly, the game sim stops loading and I get a "wrong checksum error".... So I had used the boolean, used the cube to make links, made shapes smaller, and changed the handrails reducing the file size....
Still a checksum error....
Other models I've seen on "Rule the "Rail!" have a chainlink of the same size and length for their engine.
The model is x-filed.
Still thinking and scratching if someone has an idea....