The bogie Y31 is a variant of the standard railway wagon bogie Y25. It is been especially developed for wagons of the combined cargo usage. This type features the same wheel base as the Y25 but with a smaller wheel diameter and with a cross beam of reduced height.
The bogie Y33 is a variant of the standard railway wagon bogie Y25. It is been developed for the use in special wagons such as the combined cargo. Compared to Y25 it features an increased wheel base of 2m. Therefore, the smooth operation at high speed is guaranteed despite its identical bogie design.
The Y33 covers a large area of operational requirements regarding wheel diameter, axle load and wagon height.