With my Brompton folded and stowed away on the train, I generally pass the time by reading but it is kind of fun just to observe other people. In particular I like to see how other bicycle-carrying commuters manage on the train.
I occasionally see one chap who brings his road race bike onto the train and he removes the front wheel, angles his handlebar with the bike standing upright on the rear wheel and then he bungies it to the rail in the door area.
He was on my train yesterday and I watched as he disembarked and noticed that he had at least four GoPro cameras mounted on his bike and one atop his helmet. This confirmed my suspicion that he is the Traffic Droid posting as SonofthewindsInc on YouTube.
I love the way he gives red cards during his commute :-)