Kaiserslautern is located on the InterCity (IC) line from Frankfurt to Saarbrücken and Munich and has direct connections to the airports in Frankfurt, Hahn, Luxemburg, Saarbrücken and Zweibrücken. In nearby Mannheim (40 to 60 minutes by train) there is a large IC-hub servicing the rest of Germany. Trains run between Mannheim and K-Town in 90-minute intervals.
Tickets can be purchased in the east wing of the station or from one of the ticket machines (dark blue with red DB logo) if you have a credit card. English directions are available on the menus of these machines and they are generally intuitive to use, with the exception of reserving seats. The DB website is one of the world's best travel websites, with accurate train schedules for most of Europe and online purchasing possibilities.