Train journeys can give you the oppertunity to stravel and speak with people you dont know, many people nowadays fear this and shy away from interaction, this makes me really sad. A chance encounter could end up being a new friend, a new soulmate, anything so take a chance ..
Be curious about the world around you. You never know what you can learn from random people and things that will add tremendous value to your life.
Ask questions, give your full attention to learning random things, buy books on subjects unrelated to your field, and give yourself opportunities to expand in new ways.