I like to feel the hinge flex under the floor with my feet when the train rounds a corner; I sense the stress of the steel as the joint keeps the heavy car connected together. I like the challenge of keeping my footing steady and pretending that it is effortless. I stand sideways in the car, legs slightly apart and knees slightly bent, and I lean against the shove of inertia when the train changes speed. I like the unevenness of the tracks to vibrate through the floor and up into my legs. I feel somehow connected to the ground while at the same time rushing over it, suspended above it.
Sometimes I'll read a book or do a puzzle, sometimes I'll listen to music. I try to stay isolated, despite the press of the other commuters in the space with me, but my concentration on the thousands of small movements of the train, and how fascinated I am with the way my body automatically reacts to each separate one in order to keep myself upright, means that I absorb every detail of my surroundings: I'll overhear a phone conversation, I'll steal a glance at the pretty girl, I'll wonder where the bald man works, I'll read the paper in someone's lap.
Occasionally a sudden shift of the position of the train will result in someone bumping into me; I smile and apologize, offer a reassuring hand, then retreat into my reverie of balance.