LT Railways Destination Signs
It is entirely natural that people watching an approaching Underground train will be want to be reassured that it is heading (or not) for the destination they want. Modern trains use electronic displays (of variable efficiency) but until the 1980s trains used roller blinds that displayed very clearly the ultimate train destination and sometimes the route.
But prior to the Second World War Underground trains used enamelled iron signs positioned on the front of each train. These sometimes included displays capable of showing line or route, or whether the train was all stations or non stop. These plates (highly collectible in some circles) had a different destination on each side and sometimes had quite a long life.
These notes simply set out some of the things known about their origin, construction and usage pattern from various collections or photographs the details of which have drifted past the author from time to time.