h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Very good entry, I enjoyed reading it. Well done.

Brings back memories of the 17:37 from Manchester Piccadilly

lovely. It took me a while to learn, this basically summarizes it. One addition- dont look like you're trying too hard. If you hold the stance like a ninja-in-training, you'll look pretty funny.

Some people do it naturally, without any thought at all.

I once observed a teenage girl, immersed in a book, stroll onto a subway car and stand with her feet together, facing the door, without looking up, for the entire ride from Manhattan to Brooklyn.

As an extension to the idea of not locking knees, when riding the London Underground on fast/bumpy lines I found that listening to music at sociably quiet levels on a walkman and swaying gently to the beat made balancing less effort.
It seemed much easier to add corrections to leg/hip movements I was already making than to initiate movements simply to correct for the carriage moving around.