HM120848/ HM120817XD TAROL4-1/4X8 Railway train bearings

The HM120848/HM120817XD is an imperial double-row tapered roller bearing (TDO — Tapered Double Outer configuration),belonging to the HM120800 series. The bearing assembly consists of two cone assemblies (Cone: HM120848) and one integrated double cup (Cup: HM120817XD), featuring a stamped steel cage.

This model is widely used in railway vehicle wheelset axle boxes and is commonly referred to in the industry as a Class B 4¼×8 railroad bearing. It serves as a core load-bearing component for railway freight cars, passenger coaches, and locomotive bogies. It is also suitable for heavy-duty construction machinery, rolling mill equipment, gearboxes, differentials, and other high-load applications.

Key Features & Advantages

1. Double-Row High-Capacity Design — The TDO double-cup configuration arranges two rows of rollers in a back-to-back orientation, enabling the bearing to simultaneously carry heavy radial loads and bidirectional axial loads. Its load capacity is significantly higher than single-row bearings, making it ideal for heavy-duty, impact-prone applications such as railway axle boxes.

2. Power-Dense Design — Optimized internal geometry delivers higher load capacity within a limited envelope, helping to extend bearing fatigue life.

3. Low Friction & Low Temperature Rise — Optimized roller contact surfaces and raceway geometry reduce operating torque and operating temperatures, extending the service life of grease and lubrication systems.

4. OE Co-Engineering — Designed, engineered, and tested in collaboration with OEM engineers to ensure premium performance in demanding applications such as railway rolling stock.

5. Special Environment Adaptability — Proprietary surface treatments and material enhancements can be applied to withstand highly corrosive, high-temperature, vacuum, or low-lubrication environments.

6. Non-Standard Shoulder Design — This part features a non-standard shoulder design. Verify the shoulder dimensions of mating components during installation (contact Timken Customer CAD for detailed shoulder drawings).