International rail is rarely one train. A traveller going from Amsterdam to Bruges rides a high-speed service to Brussels, changes platform and takes a regional train to the coast. The rail module finds those connections, keeps each leg with its own operator, seat and fare conditions, and sells the whole journey as one booking with one payment.
It also sells rail passes, so a traveller who plans many trips can buy a global or country pass and reserve seats on the trains that need it. Domestic train ticketing with class quotas lives in the trains module, and sea and road legs come from ferries and buses.
Every plan includes the source code. Compare the editions on pricing or book a live demo to see a journey booked end to end.