Reverse image...
Push me-pull me engines. Forward and reverse in order to get the cars (or themselves) where they want them to be for whatever purpose they are working towards.
Midnight Special - the beam of light. Communicating through light/beams/signals?
Edit: Here's something interesting that keeps coming up when I do searches: Australia.
Lead Belly had a sister named, Australia.
Sean Williams is an Australian writer who wrote The Grand Conjunction in 2009, a book in the Astropolis series.
That's right, mate - Australia.
And here's something really fun - Dave Lavery spent part of his life growing up in Australia. To hear him talk about it, he has very fond memories of Australia. He was in Alice Springs, Northern Territory. And in remembering about some of Dave's adventures, I remembered
this thread that was posted by Beth Sweet. It was so cool. It's about a book.