Between 1928-1934 the Latvian Railways have purchased in German factories and assembled with their participation but in Latvian workshops, a total of 20 broad gauge tank locomotives of Tk series. A characteristic feature of the structure was a single motorized axle. The solution of this kind, dedicated to usage of passenger trains composed of 2-3 cars on the lines with a light profile, constituted an alternative to motor vehicles. The project have foreseen the opportunity to change the wheel sets for such adjusted to 1435 mm clearance. In 1945 on the Polish State Railways operating area two Latvian locomotives of Tk series were identified and included in the inventory. The first one was named OKa1-1, the other remained under the partially modified old mark TKa242. The OKa1-1 locomotive apart from a short stay in the locomotive shed Fosowskie (28.05.1950-1.01.1951), belonged to the locomotive shed located in Łazy. Its tasks were connected with the staff trains within the area of the station between I and V police station. The locomotive performed its duties to December 1968. It was deleted from the Polish State Railways inventory on 22 March 1969 and later transferred to the Railway Museum in Warsaw.