What is the purpose of that (green) light under the escalator steps where you first get on, and (maybe) at the exit? And, what kind of light source is it?
The Master Speaks: Why are there Green Lights under Escalators?
Oh, I thought it was about the Shel Silverstein book. 
gives a soft light to the midgets on the treadmill.
Green better off sets the steps. They are not required at this time. When they started to put them on escalators they were on both landings. Then they were only put on the lower landings.
Otherwise it is too dark for the troll who lives under there to read.