Lublin has railway connections with all the main cities in Poland. The schedules and the prices can be found at the Polish railway company’s (PKP) website: http://rozklad-pkp.pl/?q=en/node/143. Below you can find information about connections with selected cities. You can reach the city center from Lublin railway station in 15-20 minutes by trolleybus no. 150 (consult timetable here: http://mpk.lublin.pl/en/?przy=3422&lin=150)
a journey from Warszawa Centralna station (you can get there from Chopin Airport by train or by bus no.175) takes approximately 2,5 hours.
There are 9 direct trains (first 5:55, last 20:58) from Warsaw to Lublin
The current timetable can be found here
a journey from Kraków Główny station (you can get there easily from Balice Airport by train) takes 4-5 hours
there are 2 direct trains (6:28 and 16:22) from Krakow to Lublin
a journey from Poznań Główny station takes 6 hours
there are 2 direct connections (6:35, 16:25) and few connections via Warszawa Centralna