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Simeon Cox MIET AMIRSE

Parsons Brinckerhoff Australia Pty Ltd

Axle counters have many advantages as a train detection system but in comparison with track circuits they are complex.  Initial use for single sections, typically replacing absolute block or single line working systems proved very successful but as their benefits were realised they have been applied to more and more intensive applications. These intensive applications, which were previously the domain of track circuits, have seen a number of hazards arise that were not previously present with the use of track circuits. These hazards may have always have existed such as the loss of broken rail detection but are exacerbated by removing track circuits or may be specific to the use of axle counters such as reset and restoration. These hazards have been managed in many ways by different railway administrations; this paper will compare a selection of  applications, the technology and principles behind the mitigation of those hazards.

The paper will also consider the evolution of the design of the axle counter from single sections, to multiplesection finally to advanced forms that communicate using open communication networks across huge distances but at the same time are closely integrated with the interlocking and control system to provide enhanced diagnostic and operational information that can be used to improve system reliability and performance.