The “traveling bar” as it was known was a widely used cell locking mechanism installed in many Canadian Prisons. “The Wheels” were threaded onto two side by side bars that ran the length of the cellblock. These bars had misaligned holes in them that would match up when the wheel was spun allowing a vertical bar to raise inside the hole thus unlocking the cell. The entire range could be spun open or each cell could be opened individually. The major hazard of this system was fire. The inmates always enjoyed setting fires to their ranges during a riot. The heat from the fire would expand the bars and the cells could not be opened.  Often the doors to the ranges would be barricaded and we could not get in to put the fires out.  The traveling bar locking system was a death trap.