When a detector senses an overheated bearing (a hot box ), it
broadcasts a recorded warning by radio to the train crew.
hump yard: When individual railcars are assigned to different trains,
a switch engine pushes them, singly or in small “cuts,” over a
hump—literally a high spot in the rail yard. Once past the hump,
a yard worker separates the cars from the engine, allowing them
to roll slowly forward by themselves, carried along by gravity
down the long, slight incline. In this manner, they are switched
onto different tracks as they go, ultimately joining up with the
journal bearing: If there is one critical part common to all railcars,
the journal bearing is it. There are two of these box-shaped bear-
ings on each axle, and essentially they bear the weight of the car
and help to distribute its weight over the axle. When a journal
bearing fails, it overheats and is referred to as a hot box . If unde-
tected, it can cause a serious breakdown.
lading: An industry term for whatever a freight car is carrying.
load limit: The maximum weight a given car is permitted to carry.
It's computed by subtracting the weight of the empty car from its
maximum allowable gross weight. The load limit is stenciled on
the side of every car.
locomotive: Also referred to as “the engine,” this is the self-propelled
machine that hauls the train. If there is more than one locomo-
tive in the consist, the first is called the “A” or “lead” unit. An
additional locomotive is referred to as a “B” unit.
main line: A long stretch of track that receives regular, heavy use.