The category Ia locomotives with the numbers 161 to 190 were 30 2-4-2 express locomotives built by the StEG in their own shops between 1886 and 1896. Compared to the numbers 65 to 122 of the same wheel arrangement, the drivers had been enlarged from 1,820 to 2,120 mm. Although the heating surface had been reduced by a bit, they had still a fairly large grate of 2.3 m². As with the earlier locomotives, the French influence could clearly be seen.

They were only operated in the northern part of the StEG network in today's Czech republic. So all remained in Austria when the StEG was split into an Austrian and a Hungarian part in 1891. Now they formed the class 24. When the StEG was nationalized in 1909, they became kkStB class 205. After World War I, 29 were still existing, but all now on Czechoslovak territory. 23 of these were taken over by the ČSD and became class 254.3. The last of these were withdrawn in 1930.