The Royal Westphalian Railway was a German rail company established in 1848 with funding from the Prussian government, which later became part of the Prussian State Railways. The network eventually extended about 315 km from Rheine via Hamm to Warburg and from Welver to Oberhausen.

The term Prussian state railways encompasses those railway organisations that were owned or managed by the State of Prussia. The words "state railways" are not capitalized because Prussia did not have an independent railway administration; rather the individual railway organisations were under the control of the Ministry for Trade and Commerce or its later offshoot, the Ministry for Public Works.