scope:

Those involved in designing train detection systems will need to use this specification.

Note This specification does not fully cover certain processor based interlockings that have integrated control and interlocking (e.g. SelTrac S40) and no track circuits, but these systems should comply with the spirit of the requirements. Axle counters used in these systems shall comply with the requirements contained within this specification.

This specification shall be used when designing:

a) train absence detectors, such as track circuits

b) train presence detectors, such as axle counters or position detectors.

Note This specification does not address vehicle configurations, axle numbers and spacing, or the EMI/EMC compatibility between the rolling stock and the train detection system. It is incumbent upon the application engineer to consider these issues when applying this specification. Reference shall be made to the Head of Road and Rail Traffic Control Systems to ensure that changes to the train detection systems do not invalidate rolling stock approvals.

Purpose

This specification details the system functions and performance criteria for train detection systems and describes their complete system lifecycle characteristics.

This specification applies the concepts of the safety signalling philosophy, as described in guidance G195B 'Safety Signalling Philosophy', to train detection systems.