For those new to the hobby or now getting deeper into it, I would like to suggest that a trip to the NMRA web site Beginner Pages at: http://www.nmra.org/beginner/ may be beneficial.
There is a large amount of information there that can be of use and answer many questions. Also, you may want to visit the main web site atL http://www.nmra.org/ to see what else the NMRA has to offer on the web.