It is possible for you to start your travel from a country which is not your home country (your country of residence).
If you live in Poland, you could, for example, take a flight to Spain, and then start your train travel. However, the flight ticket would need to be purchased and paid by you.
You can receive a ticket to fly to certain insular countries (Malta, Cyprus, Iceland and Ireland). This can be requested to the Travel Team by sending in a request. Places are limited and will be booked based on a "first come, first served" basis.