Wow, this has been really fascinating!
I'm wondering if this is a spectrum instead of a yes or no situation. For me, one train of thought can spiral into a hundred things. Going back to arebelspy's example of cat-horse-motorcycle, I might see a cat, and it might remind me of a cat from childhood, and that time I put him in a silly costume, but it'll also remind me of a horse and the lessons I used to take, which reminds me of a motorcycle... and all of a sudden I'm visualizing my childhood cat on a motorcycle. That's a poor example.. what I'm trying to get at is one seed of thought turns into a massive tree, and I'm left with figuring out how various branches came from the same thought. My mom and I have always shared a similar sense of 'logic,' as we called it. She'd ask me one thing, I'd respond with something seemingly completely random (but she'd follow along), and several sentences later we're talking about something completely different, leaving my poor dad in a state of confusion. I've only met one other person with a similar sense of 'logic,' and we always just joked it was because we were silly.
Sometimes it's overwhelming, and I do tend to lose my train of thought easily. Imagine that, for your average person, a train of thought is like a faucet that's running. For someone with aphantasia, it's off, or running in a very controlled manner. For me, it's like a pipe burst. All these thoughts and visualizations all over the place. It's something I've learned to "control" (as in, I am able to focus on a single task and get work done), but I need time specifically to space out and day dream, to let my mind go off leash.