Patents for E01B 3 - Transverse or longitudinal sleepers; Other means resting directly on the ballastway for supporting rails (1,703) | |
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11/1976 | |
11/30/1976 | US3994436 Composite railway tie |
04/1976 | |
04/06/1976 | US3948010 Reinforcing device for an element of prestressed concrete |
03/1976 | |
03/16/1976 | US3943818 Railroad tie |