For the use case of playing on a train, if it is literal, you should play a board game that doesn't need a board. A great one IMO is "Hive". It is abstract, so

For the use case of playing on a train, if it is literal, you should play a board game that doesn't need a board. A great one IMO is "Hive". It is abstract, so no story or narrative, but it is easy to learn the moves, very portable, easy to play on any surface and can be very deep in its strategy.