NR RT/E/C/10049 ISSUE 1 PDF

Signalling relays used in BRS SW67 typical circuits on Railtrack' s Infrastructure. The Risk Assessment has been carried out using circuit drawings whose issue serial is shown on the supporting documents against each relay description and dated between 1990 and 1992.

PURPOSE

This Code of Practice lists relays used in BRS SW67 Typical Circuits that have been assessed as not requiring servicing, to be used in conjunction with RT/E/C/10048 "Signalling Code Of Practice For Relay And Searchlight Mechanism Servicing" to determine a servicing requirement for other relays.

1. Relays performing functions listed in this table do not require servicing provided that the critical circuit assumptions are valid for the specific relay in question.

2. In some cases, additional or alternative checks or tests on the relays are specified, and these should be applied at the stated frequencies. Nothing in this Code of Practice removes the obligation for checks laid down in Signalling Maintenance Specifications to be carried out at the appropriate intervals.

3. Relays which are repeat functions of the relays listed in this table must be serviced unless the table explicitly states that repeat relays are also exempt. Where repeat relays are exempt, the critical circuit assumptions and safety checks applicable to the first relay also apply to the repeat relay.

4. ‘Mothballed circuits' , where relays are permanently energised or de-energised, require attention only on reliability grounds.