scope:

This Work Instruction addresses the requirements of and applies a change control process to all hardware and software changes for telecoms equipment for which there is an existing product acceptance certificate signed by the Head of Telecoms Engineering.

This Work Instruction applies to Network Rail telecoms engineering staff. Manufacturers may use this procedure or may use their own alternative procedure as long as it has been approved as suitable by the NST portfolio owner and listed as such in the certificate.

This Work Instruction excludes "like for like" hardware changes which are made to correct faults. These are covered by maintenance procedures.

This Work Instruction excludes user changes allowed as selection options by the manufacturer or user unless the selection of the option is specifically prohibited in the product acceptance certificate.

This Work Instruction excludes commercial and financial considerations associated with a change but accepts that it may be necessary to upgrade systems to a specific software level in order to maintain 3rd line support contract arrangements.

Purpose

This Work Instruction addresses the requirements of product acceptance when changing hardware or software on systems that have previously gained acceptance.

The Work Instruction mandates a process to confirm that all software and hardware changes to operational telecoms equipment, for which there is an existing product acceptance certificate signed by the Head of Telecoms Engineering, are carried out in a structured and controlled manner, and are planned so as to minimise the risks of disruption to equipment, systems and train service plans.