| Year | 1923 |
| Date | 23-Aug |
| Volume | 49 |
| Issue | 1,165 |
| Page | 206 |
| Category | Railway |
| Part | 1 |
| Title | Some Notes on the Development of Railway Signalling |
| Author | E.H.Ellingham |
| Notes | Historical Outline. Three-position signal in 1841, Baronowski's signal operating machine, audible signal gear N.B.R. 1865, Mr Gregory's locking frame, point indicator, automatic electric signals, Brighton Railway |