A childhood belief about trains

I grew up in south London, and there was a London Underground line and a main line railway near us. Both were electrified with live rails, so I thought all railway lines were live, until one day we went to a preserved railway. As we were walking around the depot yard I said to my Mum "It's dangerous to step on these tracks. Aren't they live?" To which she answered that that was only on the Underground and the Southern Region (and a few other places such as Merseyside). My Mum tells me that as a child she had likewise thought that all railway lines were live. It didn't occur to her that steam trains didn't need live rails! Still, I suppose it is safe to think that, as it deters you from trespassing on railway lines!