| 1927 UNION SWITCH SIGNAL CO Railway Signaling |
| 1927 DAUGHERTY Signal For Road Vehicles Patent |
| 1927 TAYLOR Signal Toy Electric Trains Patent |
| 1927 SULLIVAN Steam Air Signal Line Connection |
| 1927 PIERMAN ALEXANDER Alarm Signal Patent Print |
| 1927 ANKELE MORITZ Rail Clamp Signal Patent |
| 1927 SMITH Magnetically Operated Signal Patent |
| 1927 ITHACA GUN CO Danger Signal Firearms Art |
| 1927 NEU Design Signal Faceplate Patent 26063 |
| 1927 ESTES Railway Crossing Signal Patent Print |
| 1927 GEBHARD JOHN Crossing Signal Patent Print |
| 1927 RAILWAY SIGNAL LTD Traffic Controlling Railways |
| 1927 GEN RAILWAY SIGNAL CO Railway Signaling System |
| 1927 MARTON Ornamentation Traffic Signal Patent 49417 |
| 1927 WORSTER Signal System For Railroads Patent |
| 1927 RUBIN ADOLPH Signal Ball Patent Print Art |
| 1927 CLARENCE ROY FARMER Signal System Railroads |
| 1927 WILEY Railway Signal Torpedo Patent Print |
| 1927 OTTO Danger Signal Attachment Locomotives |
| 1927 UNION SWITCH SIGNAL CO Electrical Art |
| 1927 STUMP Collision Signal Switch Patent Print |
| 1927 CLYDE Sunken Ship Signal Buoy Patent Print |
| 1927 WALDEN Railway Track Signal Patent Print |
| 1927 STEFAN Causing Vehicle Signal Lights To Flicker |
| 1927 UNION SWITCH SIGNAL CO Railway Braking Art |
| 1927 INTERFLASH SIGNAL CORP Day Night Beacon Art |
| 1927 COOPER TAYLOR Stolen Car Signal Patent |
| 1927 LUCAS PIPER Signal Lamp Patent Print Art |
| 1927 UNION SWITCH SIGNAL CO Railway Skate Operating |
| 1927 RALPH Automatic Railway Signal Patent Print |
| 1927 GAMMETER Pyrotechnic Signal Patent Print |
| 1927 LAW Overhead Signal Mirror Patent Print Art |
| 1927 Boy Scout Signal Detroit Newsletters 3 OLD issues |