Canadian Railroads > Cdn RR lantern question

Hi all, this lantern was gifted to me and comes from the CN in Toronto, I would like if soemeone could tell me the reasons it has four blue lenses and thus for what purpose this type would be used for with all same colors lenses and how/on what it would be mounted It doesnt have a hook as for hanging on caboose or passenger holder nor has a square underside peg to sit atop a switch post, but has a rusted lower part all around that suggest some kind of band type holder, anyway would appreciate any insight I apologize for the furst dont know why it got rotated when uploaded)
C
 

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The nighttime version of the "blue flag" prohibiting movement of equipment by anyone other than the one who placed the blue flag/light?

I thaught of that but never seen a full size lantern  used for that purpose, a smaller brakeman type lantern yes so not sure.