Here are the possible solutions for they often have red lines clue
Answer
Clue
Relevancy
metros
Clue
They often have red lines
Definition
METRO, an urban railway system running wholly or partly underground
newt
Clue
Gingrich who said "females have biological problems staying in a ditch for thirty days because they get infections and they don't have upper body strength"
Definition
a tailed amphibian of the salamander family, also EWT