Hello Johnny's nanny and a warm welcome to the forum. I think that you will find this link useful to show where the main railway lines are.
http://www.nationalrail.co.uk/passenger_services/maps/
Also available on the national rail website are timetables for all the services and station plans of what's whereon each station. A word of caution though, not all stations are of an open nature, some have platform tickets available, some don't. Personally I like to get out into the country and find a quiet spot by a rail line, an afternoon in summer with birds singing and the trains going past; perfect!
Hope this helps, don't worry about asking questions, we'll do our best to come up with the answers for you.
Regards, 62440.