You have some good suggestions above, and yes, proper blocking would be a huge help. Make sure that the cast and crew don't have any need to get close to the edge of the stage.
Now, since you said the markers need to be movable, here's a quick and easy suggestion. Get some poster board (it comes in lots of colors) and make up some "triangular tubes," say two inches on a side, and as long as you need them. Attach glow tape to one side and place them so the tape faces upstage, some distance from the edge of the stage. Use as many as you think you need. They are free-standing, so taping them to the floor is not necessary, although it might be useful. Here' a quick sketch:
------------------------------
George F. Ledo
Set designer
www.setdesignandtech.wordpress.com
www.georgefledo.net
------------------------------
Original Message:
Sent: 01-07-2025 08:14
From: Erich Friend
Subject: edge of stage marker light
Many of the LED strips / rope light solutions are not appealing for the audience as they are visually distracting and draw attention away from the performers. The only really functional solution I have found is the EdgeLyte product from Future Light (https://www.future-light.com/products/edgelyte.html). The parts are custom made to fit the dimensions of your stage apron, and the LEDs are recessed and directional so only the performers see them. They are a bit tedious to install as it requires some skill with a router and ingenuity to get the low voltage wiring out to the stage apron without creating a trip hazard or fire hazard. It can be done with some planning.

For stages with removable pit fillers we have installed them in the pit filler panels along edges and interconnected them with pluggable wiring that comes back to a specialized low voltage connector on the apron face. This way the safety feature can be available for either stage configuration.
I consider the stage edge safety lights to be important enough that we power them from an emergency lighting circuit so in the event of a power outage / black-out the edge lights stay on to reduce the likelihood of someone stepping off into the abyss. Resist the urge to put them on a switch or dimmer - they need to be ON all the time 24/7/365.
If you wan a passive solution, then consider building this:

------------------------------
Erich Friend
Theatre Consultant
Teqniqal Systems LLC
Original Message:
Sent: 01-02-2025 11:57
From: Christine Causer
Subject: edge of stage marker light
Hello,
I am looking for suggestions to replace the rope light I use to light the edge of the stage. The stage has pit platforming that comes out for musicals so the edge of the stage marker needs to be moveable to accommodate removal of platform sections. Any suggestions would be appreciated.
Thanks!
------------------------------
Christine Causer
Teacher/Production Manager
Burlington Township High School
NJ
------------------------------