Tracking system for the train tickets (Web service).
https://api.trackseats.info/ (Beta testing, registration by invitation only)
Please find brief API specification in wiki.
Sometimes hard to get train tickets for popular routes, you should do it in advance and there is no guarantee that tickets still here. This system can help, if someone returns their tickets then the system will send email notification.
Integrated only with Belarusian train tickets system for now.