"Lantern with 4 sides of differently coloured glass. Green Red White and Blue. Might have been used at a railroad station <- unsure."
A: "It is, the colors correspond to different actions. White/clear is to stop another train, blue is for marking equipment not to be moved, green is proceed with caution and red is stop."
The polystyrene balls are used for insulation between the walls. After time they will come out during windy weather.