The bolster is used to transfer the load through the spring group to the side frames mounted at the ends of the beam, and is a box-section casting with a cast base and a platform for mounting the side bearings (version 7020.00.001-02 with cast side bearings).  Bolster version 7020.00.001-02 is a complete analogue and is fully interchangeable with the Bolster version 100.00.001-6.  This bolster is part of the 18-7055 bogie, which is the analogue of the 18-100 bogie.

The bolster is designed to complete the bogie of the biaxial three-element bogie models 18-7020 and 18-7055, as well as bogies of other interchangeable models with an axle load of 23.5 tf for a track gauge of 1520 mm.

Side frame is designed to absorb the loads transmitted from the car body, to transfer them to the wheelsets, and to accommodate the spring group.  Side frame is a casting with a slot in the middle part to accommodate the spring group and slots at the ends to mount the wheelsets with box unit.  The frame design has been upgraded with the installation of a bracket for the parallel brake pad retraction mechanism, which increases wheel life and contributes to even wear of the wheels and brake pads.

Side frame is designed to complete the biaxial three-element bogie models 18-7020 and 18-7055, as well as bogies of other interchangeable models with an axle load of 23.5 tf for a track gauge of 1520 mm.