Compact tapered roller bearing units incorporate polymer spacers to reduce fretting and specially designed seals to lower bearing operating temperature and provide longer grease life and longer maintenance intervals. 

The bearings consist of two inner rings, one common outer ring, two tapered roller and polymer cage assemblies, a central spacer, grease fill and two sealing systems. Lateral spacers, backing rings and end caps with locking devices can also be added.
In the railway industry, reliability is vital to profitability.  compact tapered roller bearing units (CTBUs) are a robust solution that help lower life cycle costs and extend maintenance intervals. 
The bearing units consist of fewer parts and offer space-saving opportunities as well as housing design simplifications. For example, the axle length can be shortened and axle bending limited. 
CBTUs integrated low-torque seals are also space-saving by design, integrated into the bearing unit NSK 6203dul1b Bearing between the outer and inner ring. This helps reduce friction torque by up to 75% compared with a garter seal arrangement. In addition, operating temperatures are reduced by 20°C, contributing to longer grease life and energy savings.