| 摘要 |
A system for monitoring the passage of trains on a rail track by measuring train length, employs track circuits which detect the presence of any part (wheel axle) of a train in any part of the track-circuit. A distance indication of the overlap of train and track-circuit is provided by an axle-driven pulse counter on the locomotive AND-ed (23) with the track-circuit 'presence' output, which is transmitted (15-19) from the trackside. Knowledge of the track-circuit length L1, either stored on the locomotive or in a central control station (31), or supplied at the time by the radio link from the trackside, enables the train length L0 alone to be deduced. This train length count is then compared at successive track circuits terminating block sections to give an indication of any discrepancy and the possibility of a carriage having been left in the section. <IMAGE> |
