"The term Prussian state railways (German: Preußische Staatseisenbahnen) 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.
The official name of the Prussian rail network was Königlich Preußische Staatseisenbahnen (K.P.St.E., "Royal Prussian State Railways") until 1896, Königlich Preußische und Großherzoglich Hessische Staatseisenbahn (K.P.u.G.H.St.E., "Royal Prussian and Grand-Ducal Hessian State Railways") until the end of the First World War, and Preußische Staatsbahn (P.St.B., "Prussian State Railway") until its nationalization in 1920. A common mistake is the use of the abbreviation K.P.E.V. in supposed reference to a mythical "Royal Prussian Railway Administration" (Königlich Preußischen Eisenbahn-Verwaltung). No such entity ever existed and Prussian railway cars acquired the K.P.E.V. logo apparently through an error originating in their Cologne division." - (en.wikipedia.org 30.01.2020)
