Last year I traded some American glass doublet lenses to a heritage railway in Scotland. In return I received these. The three on top are your normal red, green, and amber aspects. The two lying down are beautiful "lunar white" lenses. An incandescent bulb shining through them creates a bluish white light. The red lens is embossed "Nazeing" and has a small "Westinghouse Brake and Signal Co. LTD/ Passed" sticker on it. One of the lunar and the green lens each have "BRE Crewe Scientific Services/"Passed" stickers on them. Crewe was a major British Railway engineering facility located in Cheshire.