In 1946, the Fablok and Cegielski factories started the production of PKP class Pt47 (pre-war PKP class Pt31) and PKP class Ty45 (pre-war PKP class Ty37) locomotives. Meanwhile, the production of PKP class Ty42 (German BR52) was in process and Poznań prepared to start the production of PKP class Ty43 (German BR42) which had been produced in Szczecin previously. The situation in the Polish railways was disastrous, so the government decided to buy 75 USATC S160 (Polish PKP class Tr201) American locomotives (on UNRRA basis), 30 British 9F (Polish PKP class Tr202) locomotives, and 500 S160 Polish PKP class Tr203) locomotives, what was left from American army in Europe. Another 100 locomotives ordered from USA (Decapol – Polish PKP class Ty246) were sent to service Śląsk–Gdynia line. In the same year, electric trains started an operating line from Warszawa to Otwock.