Which type of lantern must never be used to give a proceed hand signal?

The red lantern is specifically designated to indicate a stop signal and is universally understood as a warning or indication that movement must cease. It is critical for maintaining safety on the railway system, as using a red lantern to signal a proceed would create confusion and potential hazards. This distinct color coding helps ensure that all train operators understand the meaning of the signals being conveyed, thus preventing misunderstandings that could lead to dangerous situations. Each color lantern serves a specific purpose: green typically signals go, blue may indicate specific conditions or warnings, and white is used for other specialized communications. Therefore, the red lantern should never be associated with a proceed hand signal, as it directly contrasts with its established purpose in rail operations.