These coffee pots were once numerous in London yet do not have coffee in them! What are they? It’s a particular design of signal on the London Underground, a very old one. They looked rather like a coffee pot so that’s their name. Coffee pot signals have been about since the tube’s early days. One of the earliest pictures I can find of these signals is this one from 1912 at Liverpool Street on the Central London Railway. From this picture its clear they were originally intended as repeater signals.
However some tube lines, especially the Northern, came complete with numerous coffee pot signals as station starters. The reason for this is not known other than in the 1900s to 1920s it was a cheap way of providing at the time a type of modern colour light signal.
The Northern LIne was in fact the last tube line to use substantial numbers of coffee pot signals in service. Not too long ago they were replaced by a new signalling system – but quite a number of the Northern’s coffee pot signals are still in service too – as relay boxes for the new signalling!
The lights in these have simply been removed and the circuits modified to adopt the new signalling system, then the pots wrapped in black tape. I suppose this approach was somewhat cheaper than complete renewal.
Here’s two examples of the Northern’s coffee pot signals in their new role. The distinct outline of these old signals can be easily seen!
New role for Old Street’s northbound platform starter. Above this is one of the new CBTC signals, known as a ‘Ready to depart’ indicator.
Tooting Bec’s southbound platform repeater clearly showing the cheap modification using black bags and tape! 🙂
The only coffee pot signals still in regular service on London’s Underground are on the Circle/Hammersmith/Metropolitan lines at Baker Street, Great Portland Street, Euston Square, Barbican and Liverpool Street stations.
They are merely platform repeaters left from the days when tube trains had guards, however at busy peak times these signals can still help platform staff whose job is to ensure everyone is safely on the trains.
These quite ancient signals, some of which must be nearly a century old, should have been withdrawn by now. The signalling replacement contract with Bombardier ended in 2013 due to difficulties. Thales has a new 2015 contract for the sub-surface lines which means these few surviving coffee pot signals will last a few more years – until quite possibly 2020.
Baker Street has just one coffee pot signal on the Circle/Hammersmith & City westbound platform. All the other stations mentioned have two, one for each direction.
Great Portland Street’s eastbound coffee pot signal high up on the ceiling.
Great Portland westbound platform coffee pot signal.
Both of Great Portland’s coffee pot signals still have a duty helping platform staff to know the state of the train starter signals due to the sharp platform curves.
Euston Square’s coffee pot signals.
The eastbound one (above) has clean sightlines whilst the westbound one’s almost hidden within a rather damp and leaky alcove. The westbound starter is quite visible so perhaps the relevant coffee pot signal is no longer so important.
Euston Square’s westbound coffee pot signal.
Farringdon and Moorgate stations have been modernised so no coffee pot signals there. Interestingly Kings’ Cross has probably never had coffee pot signals. The station was in fact built during the 1940s thus more modern signals would have been used, namely Westinghouse repeaters like those found elsewhere such as at Edgware Road.
Barbican has a pair of coffee pot signals. The following pictures show the one on it’s eastbound platform. Its clear from the second picture that these signals are quite old.
The eastbound at Barbican.
Close up of the eastbound signal at Barbican.
This is the westbound coffee pot signal at Liverpool Street. It still performs a duty at this very busy station. That guy happened to alight from the train as I took the picture!
Liverpool Street station has a very interesting coffee pot signal on its eastbound platform. Its paired together with a modern signal. The coffee pot assists with the eastbound trains whilst the other is a repeater for the signal that controls the crossing at the west end of the platform. This is used on the rare occasion trains need to be turned round at Liverpool Street.
Liverpool Street’s coffee pot signal.
The modern platform repeater next to the coffee pot. The coffee pot’s hatch giving access to it’s light bulbs can clearly be seen.
The London Transport museum has some coffee pot signals here’s an example