I spend a lot of time on the train (6 hours a week, minimum). I love the hustle and the bustle, the people and towns flashing by. I've also gotten really good at doing all the things I need to do on a train. Eat sushi, write, do my nails, I've even given myself facials on a train.
Perfect train outfit.
The key is to layer, because the temperatures are extreme and change in a heartbeat. Wear black if you're going to be eating, and relax. There will be bad smells, annoying people and long waits. But soon enough you'll get to the next station and then, everything and anything can change.