On a westbound tube train today I found myself in view of the Barbican’s coffee pot signal right opposite my train window, so what better than to take a picture showing the off-side of one of these signals?
The method of construction of these coffee pot signals is more clearer in these pictures. The top of the signal (the lid) has a gap to allow heat from the signal bulbs to escape. The gap underneath the lid is clearly visible as are the brackets (there are four of these) that support the lid itself.
Originally the inner surface of the hoods surrounding the lights would have been painted white to give extra visibility. That would have been neccessary when these signals were first introduced. With much more powerful bulbs using fresnel lenses, it seems hardly worth painting the hoods, although one could say they would look much better if they were painted and maintained as they once were.
The closest examples of how they should look are the eastbound signal at Great Portland Street and the westbound at Euston Square. Great Portland Street’s has larger than usual hoods yet clearly shows how they should be painted. The gap underneath the lid can be clearly seen in the Euston Square sample.
This post complements that I did recently on the tube’s remaining coffee pot signals.