Transport London's Underground system is called the tube . Do not refer to London's Underground lines as the blue line or the red line. Many underground lines have similar colours and Londoners won't know what you are referring to. Maps can be obtained from tube stations or at the main railway stations. Check the destination on the front of the train since most lines have branches and not all trains go to the end.
Trains are usually very frequent unless there is a problem.
Many escalators don't work. On the escalators remember to stand on the right as the left side is used by people walking up or down. Don't stop at the foot of the escalator as people following will have nowhere to go. Try avoiding travelling during the rush hour. If you're confused, ask.