Metro Smart Card Application

I had a coding exercise today as part of an interview, where in I had to design a metro smart card application. Requirements -

1. There is a metro line having 10 stations linearly from A1 to A10.
2. Price per station is Rs. 5.5 (for weekends) and 7.0 (for weekdays)
3. The metro line is 2-way.

I did it but I am not sure if that is correct. Of course I am getting the correct output but design is something which does not have one answer. I have created some class diagrams based on what i did today. This is maximum I could do. Can you guys please help me make it better?