| 1928 GILSON Railway Traffic Controlling Art |
| 1928 ERICKSON Street Traffic Signal Design Patent 49410 |
| 1928 UNION Railway Traffic Controlling Art |
| 1928 MCCANN Railway Traffic Controlling Art |
| 1928 LUCAS Railway Traffic Controlling Art |
| 1928 GRONDAHL Railway Traffic Controlling Art |
| 1928 WAGGAMAN Design Traffic Signal Casing Patent 49386 |
| 1928 THOMPSON Railway Traffic Controlling Art |
| 1928 SNAVELY Railway Traffic Controlling Art |
| 1928 UNION SWITCH SIGNAL CO Railway Traffic Controling |
| 1928 BUTTRON Traffic Signal Observer Patent |
| 1928 JOHN Traffic Signal Apparatus Patent Print |
| 1928 BEALL Railway Traffic Controlling Art |
| 1928 ZIERDT Railway Traffic Controlling Art |
| 1928 SKENE Railway Traffic Controlling Art |
| 1928 FAILOR Railway Traffic Controling Art |
| 1928 ACKERLY Railway Traffic Controlling Art |
| 1928 FAILOR Railway Traffic Controlling Art |
| 1928 LEE Railway Traffic Controlling Art Print |
| 1928 SMITH Railway Traffic Controlling Art |
| 1928 BAUGHMAN Railway Traffic Controlling Art |
| 1928 ALLEN Railway Traffic Controlling Art |
| 1928 Metal Traffic Marker Morrison Hotel Chicago pic ad |