| 1957 CLARK Light Signal Projector Patent Print |
| 1957 GEN RAILWAY SIGNAL CO Railway Car Retarder |
| 1957 GEN RAILWAY SIGNAL CO Railway Track Circuit |
| 1957 NUTONE INC Chime Signal Patent Print Art |
| 1957 BERTHEL Radio Transmitting Receiving Signal System |
| 1957 MCCLELLAN Baler Tier Signal Patent Print |
| 1957 FARRELL Basketball With A Visual Game Signal |
| 1957 GEN RAILWAY SIGNAL CO Searchlight Signals |
| 1957 HARRY Portable Self Contained Signal Warning Light |
| 1957 DEERE MFG CO Baler Tier Signal Patent Print |
| 1957 JOSEPH MCEVOY Chime Signal Patent Print Art |
| 1957 MCGRAW ELECTRIC CO Light Signal Projector |
| 1957 KUEHN Signal Generator HYCON Patent 24856 |
| 1957 WASLEY Bent Arm Signal For Golfers Patent |
| 1957 GASACCUMULATOR Sound Signal Transmitter |
| 1957 GEN RAILWAY SIGNAL CO Track Circuit Railroad |
| 1957 GEN RAILWAY SIGNAL CO Switch Machine Patent |
| 1957 GEN RAILWAY SIGNAL CO Car Retarder Control System |
| 1957 OBERG Sound Signal Transmitter Art Print |
| 1957 MOCK Controls For Signal Circuits Patent |
| 1957 PROGNER Speed Signal Means Patent Print Art |
| 1957 WEBER Radio Transmitting Receiving Signal System |
| 1957 MICHAEL Chime Signal Device Patent Print |
| 1957 KING JOSEPH Signal Device Patent Print Art |