PKP received 75 S160s from UNRRA and numbered them Tr201-1 through 75; a further 500 arrived from the USATC as class Tr203, numbered Tr203-1 through 500.
In PKP service, the boiler pressure was reduced to 13 bar, and the maximum speed was set to 65 km/h. Further modifications included fitting Trofimov piston valves, electric headlights, and side doors on the cabs.