Where i live, in Folsom CA, there used to be a railroad that ran from Sacramento all the way down to where old Folsom is now, i believe it even became a SP subsidiary at one point. When local light rail was built, they actually traced the line of the old railroad. As for the fate of the railroad itself? It basically closed down and most of its trackage torn up, a small sliver of its Folsom railyard remains, now being used by a "historical railroad". (i say that word lightly as all they have to operate is rail speeders) Not all of the trackage was torn up, near where light rail leaves Folsom city limits some of the trackage remains, being used to service industries between Sacramento and Folsom, Highlight industries include:
An Aerojet research center, (the trackage is now closed off and unused, from what can be seen on google earth the tracks run quite close to the old booster test harnesses)
a steel company (i saw a UP SD or GP series diesel service this industry once)
and finally a old branch where trains once delivered munitions to B-52s that were stationed at what was Mather AFB back in the day.
Now as for some of the more well known nearby rail infrastructure, I have seen:
Sacramento (California state RR museum, Sac station, whats left of the sac shops, Cap corridor, the old WP station)
Roseville yard (i go railfanning there)
As for the RRs i have near me.
UP
AMTRK
BNSF
Light Rail (i don't know if that counts but...)
So all and all.....i got alot of neat stuff nearby.