These are use in interlocking where GEC was the main contractor.
Railway Signalling Relay connectors for SGE, GEC / Alstrom BR930 spec find their ideal use in railway signaling systems for applications involving the BR930 switchgear.
Railway Signalling Relay connectors for SGE, GEC / Alstrom BR930 spec
Railway Signalling Relay BR930 type Connectors for Westinghouse Style Bases
Polarised Signalling Relay SYX Type E 250 ohm by W.R.Sykes Clapham London Tested
railway signal relay contact time delay QMT2 code 190 24 volt (7)
railway signal relay contact style 699 code 105T 24 volts (3)
railway signal relay contact (4)