[JasonB]

I've always loved the "slippery road" sign, where the tyre tracks swap over. I also love a thread which meanders off into more interesting territory.

But I have a couple of questions.
First, my brain can't compute half zero. Mathematically half of zero is still zero?

Secondly, my understanding was that model railways usually worked on the gauge of the track, the width between the rails. Which of course means that several different scales could operate on a particular gauge. So a narrow gauge train at a larger scale could operate on the same track as a standard gauge train at a smaller scale?

It's a murky, and confusing world out there. But at least it's better than complaining about Facebook.