Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4886226 | Broken rail and/or broken rail joint bar detection | — | 1989-12-12 |
| 4878638 | Combination frequency loop coupling for railway track signalling | James R. Hoelscher, Frank A. Raso, Barry L. Smith | 1989-11-07 |