PassengerHolder can accept passengers
PassengerHolder can release passengers
PassengerHolder can release passengers
PassengerHolder can reject Passengers when it is full
Passenger can touch in at a station
Passenger can touch out
Station can dock a Train
Station can undock trains
Trains can dock carriages
Train throws an error when it has too many carriages
Trains can be transferred from one Station to another
Shared_examples removed