Java Programming

Hi guys,
I'm planning to design and implement a program to act as a train timetable. The user of the program should be able to select
A start destination
A destination station
A travel date
and then be shown a suitably displayed list of train times from the selected day between the selected stations and with journey times (duration of each journey)
I still can't figure out how to approach the problem.
can someone point me to some open source java project for trains timetable ?
if not can you give me hints on how to desing and code this system ?
thanking you.