| 1937 CRAGO Railway Traffic Controlling Art |
| 1937 THOMPSON Railway Traffic Controlling Art |
| 1937 WESTERN RAILROAD SUPPLY COMPAN Traffic Signal |
| 1937 HITCHCOCK Railway Traffic Controlling System |
| 1937 POWELL Railway Traffic Controlling System |
| 1937 WILLING Railway Traffic Controlling System |
| 1937 GODFREY GORT Traffic Signal Patent Print |
| 1937 SPRAY Railway Traffic Controlling Art |
| 1937 YOUNG Railway Traffic Controlling Art |
| 1937 ALIEN Railway Traffic Controlling Art |
| 1937 ALLEN Railway Traffic Controlling Art |
| 1937 ALLISON Railway Traffic Controlling Art |
| 1937 BURRESS Vehicular Traffic Control Signal |
| 1937 VANHORN Railway Traffic Controlling Art |
| 1937 GEN Railway Traffic Controlling System Art |
| 1937 UNION Railway Traffic Controlling Art |
| 1937 HARWIG Railway Traffic Controlling Art |
| 1937 VANTASSEL Railway Traffic Controlling Art |
| 1937 O'HAGAN Railway Traffic Controlling Art |
| 1937 GENERAL RAILWAY SIGNAL CO. TRAFFIC CONTROL MANUAL |