That's an interesting build thread you linked to, Bernie, and an interesting project, too. I didn't know that such a thing as a tricycle with caterpillar tracks existed.
Is that Meccano chain you are using? If so, I might come back to you regarding its strength. I've an idea for a project where a slimline chain like that would be useful. First, I need to find my fisherman's scales to find out how much pull is required to move what needs to be moved.
Andy