The end of each axle on a pair of wheels under a freight car extend into a journal box, and rotates under a brass sleeve. If there is not lubricant between the brass and the axle, then friction will cause that journal to run hot. Hot boxes are also possible on axles equipped with roller bearings.
Overheated journal or bearing. Also called hub. This was a frequent cause of delay in the old days but is virtually nonexistent on trains that are completely equipped with ball-bearings. Trainmen are sometimes called hotbox detectors
an overheated wheel journal
An overheated axle box. Usually the result of insufficient lubrication, or excessive speed.
This is a term used to describe an axle box that has a problem, such that the friction heats up the casting. This can be cracked bearings, or lack of lubrication. Generally very bad news.
Overheated wheel journal or wheel bearing which usually causes journal packing to burn and smoke.
On friction bearings, an overheated journal bearing.
Hot Box (or simply Box) is a non-contact team sport which is similar to Ultimate, but played on a smaller field and with fewer players. Like Ultimate, the object of the game is to score points by passing the disc into the endzone; however, in Hot Box there is generally only one end zone and it is of much smaller size than an Ultimate end zone. In this way, Hot Box is a "half-court" (see basketball) variant of Ultimate.
A hot box is the term used when an axle bearing overheats on a piece of railway rolling stock. The term is derived from the journal-bearing trucks used before the mid 20th century. The axle bearings were housed in a box that used oil-soaked rags or cotton (collectively called packing) to reduce the friction of the axle against the truck frame.
