Trains

there are several rail operators in Poland:

PKP Przewozy Regionalne - local and fast (P, Pospieszny) trains without seat reservation

PKP Intercity - IC, EC, EN, Ex(express), TLK (Cheap Rail Lines) trains - all with seat reservation. PKP IC serves the only daylight connections on Warszawa-Gdansk-Gdynia and Warszawa-Poznan lines. It is also the owner of restaurant, sleeping and couchette cars.

Koleje Mazowieckie - local passenger trains in Warsaw area and a summer slow train to Gdynia "Sloneczny"

Szybka Kolej Miejska (SKM) - some local and city railway in Tricity (Gdansk Sopot Gdynia) and surrounding lines (to Wejherowo, Smetowo, Elblag)

Warszawska Kolej Dojazdowa - warsaw suburban line (600 volt) Warsaw-Podkowa Lesna-Milanowek/Grodzisk Maz. Radonska

There are various special tickets, such as "Turystyczny" valid from 18.00 Friday to 6.00 Monday for local and fast (pospieszny) trains of PKP Przewozy Regionalne and Koleje Mazowieckie companies. Cost - 70.00 zł (2. class), 99.00 zł (1.class).
There is also a similar ticket for 7 days