Simplify the following text for a Grade 5 native English-speaking person.
Original: The system consists of 70 stations on six narrow-gauge lines , running to Midland , Armadale , Fremantle , Clarkson ( terminus of the Joondalup line ) and Mandurah .
Simplified: The lines are named Joondalup , Midland , Fremantle and Armadale . The new Mandurah line will be open late in 2007 .