Hot Box.

    Old railroading term for an axle running hot in its journal box.  Trains have a lot of axles, four per car.  In the old days, before 1955 or so, the axle bearings were friction bearings.  The end of the steel axle rotated inside a solid brass bearing inside the journal box (square box with a tip up lid on each axle).  The journal box was filled with cotton waste soaked in oil to keep the bearing cool.  Trainmen used to walk up and down the train carrying huge oil cans and giving a good squirt of oil into every journal box that needed same. 

Freight trains had cabooses, in which a couple of trainmen rode to keep an eye out for hot boxes. The cupola on top of the caboose was used to eyeball the train looking for hot boxes that might be starting to smoke. 

  When a hot box was spotted the train was slowed, taken to a siding, and the hot box oiled to make it happy.  Trains did not proceed with smoking hot boxes for fear that the hear might melt the end of the axle, dropping the wheel assembly crosswise onto the track, and causing a serious accident.

Roller bearings came into service in the 1960’s, and are universal today.  They are much less prone to hotboxes than the traditional friction bearings.

There is video from that train wreck in Ohio showing one of the car trucks not just hot, it was engulfed in flames.  The train crew should have seen it.  They failed to do so, and ran the train until the axle did fail and wreck the entire train.

The TV newsies haven’t asked why the train crew failed to pull off onto a siding.