Moorgate signal cabin on the Northern Line was opened on the 11th April 1937, with a 'B' style frame and was in use until 1976.when the line was transferred to British Railways. As can be seen from the picture is was a small frame of just 11 levers, and obviously built into a tunnel wall.
The 'K' Style lever frame at Moorgate was as you can see here was only 11 levers in total, looking closely at the picture levers 5 & 6 are the point levers for the crossovers and all the other levers appear used for signals, 11 appears to be the Outer Home signal, 7-10 appear to be the Inner Home signal. So I guess 1-4 are for signalling trains in the opposite direction as Moorgate was a terminus station.
Owen writes 'There were just two signal boxes on the whole of the Northern & City line. One at Drayton Park and here at Moorgate. Like all tunnel boxes, it was very primitive. It had a very early Start up since there was no night shift here and I lived at Acton then. Picture is © of Owen Smithers and is reproduced with permission of © Owen Smithers.
Owen writes 'Moorgate on the Northern line is another hot and dirty tunnel signal box manned during the day for emergencies. During the morning rush hour the signalman had to man Clapham Common signal box. Again for emergencies. Never took a photograph of it or Stockwell box. In my early years, the Signalman used to drop off at Kennington to cover the two signalman's meal relief's after 10.30. In my day he was Mr Harry Norman once a gentleman's servant in Norfolk who joint LT when the war broke out since it was a reserved position. After the war he remained until his retirement. I real perfect Gentleman working with the roughest you could wish. This practice ceased and dealt with by the local Station Foreman '
Picture is © of Owen Smithers and is reproduced with permission of © Owen Smithers.