| 1937 CLARK Automatic Crossing Gate Patent Print |
| 1937 PFLASTERER Controlling Highway Crossing Signals |
| 1937 UNION Control Highway Crossing Signals Art |
| 1937 VANTASSEL Controlling Highway Crossing Signals |
| 1937 O'HAGAN Control Highway Crossing Signals |
| 1937 WHITE BENJAMIN Crossing Gate Patent Print |
| 1937 JOHNSON Railroad Crossing Signal Patent |
| 1937 SORENSEN Control Highway Crossing Signals |
| 1937 ASSOCIATED Highway Crossing Signaling System |
| 1937 STAPLES Control Highway Crossing Signals |
| 1937 CRAGO Controlling Highway Crossing Signals |
| 1937 ALLEN Control Highway Crossing Signals Art |
| 1937 AUTO FLAGGER CORP Railroad Crossing Signal |
| 1937 NELSON Highway Crossing Signaling System |
| 1937 PELIKAN Control Highway Crossing Signals |
| 1937 WILSON MERCER Crossing Signal Patent Print |
| 1937 GREGORY Railroad Crossing Signal Patent |
| 1937 VANHORN Control Highway Crossing Signals |
| 1937 YOUNG Control Highway Crossing Signals Art |
| 1937 JOHN H SOUTHWELL Crossing Gate Patent Print |
| 1937 UNION Controlling Highway Crossing Signals |