| Year | 1923 |
| Date | 13-Sep |
| Volume | 49 |
| Issue | 1,168 |
| Page | 291 |
| Category | Railway |
| Part | 4 |
| Title | Some Notes on the Development of Railway Signalling |
| Author | E.H.Ellingham |
| Notes | Signal Mechanism. Signal back blinder, signal repeater, operating switch for signal repeater, ground signal, distinguishing distant signal lamp, slotting gear, mounted at the foot of the post, slack wire controller |