A former BR(W) cast Alloy sealed release cabinet, this devise was fitted to the block shelf and connected into a track circuit system. Should a track circuit fail and show "Occupied" preventing the points from being moved the signalman is allowed to break the glass and hold down the release button inside. This allows the lever to be released to operate the points and over ride the system. This would of course only be allowed in exceptional circumstances and and entry made in the block register, the lineman would have to be called out to replace the glass and sign a new lable. This cabinet has an original unused lable and spring clip.