Freight trains in south Austin

We live in south Austin, and every night we hear trains running
up and down the line.  Looking at aeronautical charts I see the
line goes all the way to San Antonio.  I'm kind of curious now:

1) What type of locomotives are being used?  Where can I see
a page that details the locomotives (year built, hp, pic
of the cab, etc)?

2) What kind of freight is most likely being carried, and
in which direction?  And for what customers?  I haven't
gotten a good look so I don't know what the consist is.
I know there's a lot of limestone quarries between AUS
and SAT, so I imagine the trains may be supporting the
construction industry in central Texas.

3) Any cool things on the Internet that show the route,
the grade, or any kind of "maps" used by the engineers?
I have no idea if there's any need for train crews
to use a map or if they just run on timetables.

4) Do the trains just go short distances, or are there
long-distance trains?  How far do the crew usually
stay on?

5) Anything else I might find interesting about this line?

When there's a train practically in your backyard it's
hard not to be curious!

Mark