Car inspector...looks at the train cars ( boxcars, passenger cars, flat
cars coal cars , etc.) and makes sure that all of the accessories such as
brake shoes are in good working order. They also did what is known as
repacking the bearings of the "journals"..the journals were where the ends
of the axles of the wheels stuck out and the frame of the set of 2 axles
rest...the set of 2 axles/4 wheels and what they rest on is known as a
"truck" or bogie. A great reference that shows a lot of this sort of thing
is "the American Railroad Freight Car" by a Mr. White ( past curator of the
Smithsonian institution transportation section). basically the job
consisted of making sure the cars were in good operating order. On a
railroad such as the DRG/DRGW going through the Mountains that job was
especially important because any component of the car that may break while
crossing the mountains could result in a major train wreck.

Switchman...They would receive a list ( switchlist) and be responsible for
making sure the right car was shunted down the right track to make up the
train. One of the main activities they did was called "BLOCKING" which
consisted of making sure cars that were going to the same destination all
ended up coupled in a row so that the entire "block" could be added to the
train that was going to whatever the specific destination was. This also
was the person who would ride the trains in some instances to make sure
those cars ended up in the right places.

American railroads were and still are heavily unionized which means that if
a "switch" needs to be thrown, no one other than a member of that union
could touch the switch or it would result in the railroad having to pay a
penalty fine.

A switch is the piece of track where the rails fork.