What’s a Journal Box?

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A journal box is a housing unit in a railway bogie that contains oil for the axle and journal bearings. It minimizes friction between the wheel and axle to prevent overheating and is made of durable material. It is positioned to prevent interference with moving parts and is easily accessible for repairs.

A journal box is a housing unit in the wheel and axle assembly of a railway bogie designed to contain the oil supply for the axle and axle journal bearings. These main bearings are actually a part of the axle and are a type of bearing that doesn’t actually move independently of the wheel. The journal bearing simply allows the movement of the wheel to be independent of the axle, which creates a frictional force between the wheel and the axle on which it sits.

This friction between the wheel and the axle must be minimized to prevent the wheel from overheating, which can make it brittle and break into pieces. The kingpin box is the method of lubrication for the inside of the kingpin bearing. Serves as a housing for the necessary lubricating oil.

Most of the newspaper boxes located on railroad car axles are machined from the same material as the axle itself. This means that journal boxes are usually made from thick steel that has been tempered or heat treated to make it strong. The box must be able to hold the lube without leaking, which means it must also be made of a material that will withstand exposure to the outside elements. The boxes are mounted on the outside of the wheel. That’s another reason why it has to be made from a durable material, since it has virtually no protection from the abuses of bumpy travel that many freight trains and rail cars have to endure.

The journal boxes are located on the outside of the wheel, directly above the axle end, and are mounted between the frame rails for the entire wheel apparatus. The location of the housing is an imperative factor in its primary function as it supplies the lubricant directly to the end of the shaft. This in turn allows the lubricant to reduce the amount of friction created between the wheel and the axle.

The newspaper box is also positioned to prevent it from interfering with any of the moving parts of the wagon wheel and brake system. This is another important ranking factor. If the journal box were to leak the lube inside it, it could end up lube the brakes or the wheel itself if it was somewhere else.

The inside of the journal box is easily accessible from the outside of the wheel. Usually, it is accessed through a hinged door that is pressure-locked to prevent leakage. It is from this point that the bearing and the kingpin case itself can be repaired or the kingpin case filled with bearing lubricant.

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