Diagnose faults in signalling equipment
Overview
This standard identifies the competencies you need to diagnose faults in signalling systems and equipment. You will carry out diagnostic tests and analyse the results of the tests to determine the root cause of the fault and its location. The signalling equipment in this standard can be for overground or underground rail transportation systems and can apply to the European Train Control System (ETCS).
You will be able to locate and diagnose faults in signalling systems and equipment where the preservation of evidence is not necessarily required. The type and range of problems and faults cover both simple and complex faults and may be either right side or wrong side failures. Where further action is required because the diagnosis of the fault is inconclusive, you will be able to follow your organisation's procedures. If the work goes beyond your limits of authority as a faultfinder then you will be able to ensure the safety of the system and preservation of evidence and hand over the work to an incident investigator or other authorised person(s).
You will identify and adhere to all necessary safety measures for yourself, others, and railway operations, including the implementation of protection and disconnection arrangements for operational safety. You will document any faults and their implications, especially on safety and performance, and report and recommend actions for recurrent defects. You will accurately determine the fault's location, nature, and history using available information and, where required, seek further details to understand the failure's impact on the signalling system's integrity.
Performance criteria
You must be able to:
P1 maintain safe working practices and comply with all relevant health and safety regulations, directives, and guidelines
P2 identify any necessary changes to safety requirements upon site arrival and report to the relevant person(s) without delay
P3 review and analyse all relevant information on the symptoms and problems associated with the equipment including fault history to establish the location and nature of the fault
P4 take appropriate action to prevent the system functionality or integrity from being compromised before starting any intrusive activities
P5 ensure that protection and disconnection arrangements are implemented to ensure operational safety
P6 investigate and determine the most likely causes of the faults, including as appropriate, selecting and following the appropriate fault investigation guide
P7 carry out diagnostic techniques in a manner that minimises the interference with other systems and equipment and is within the limits of your own authority
P8 select, use and apply diagnostic techniques, tools and test equipment appropriate to the symptoms of the fault to locate the fault
P9 confirm the nature and location of the fault and the effect on the integrity of the operational system
P10 identify and analyse the implications of the fault(s) for other work and for safety considerations and report the implication of the fault(s) to the relevant person(s)
P11 analyse the evidence gained to draw valid conclusions about the nature and probable cause of the fault, including as appropriate, the effect of environmental factors, maintenance frequency and techniques, recurrent defects, defects in the equipment
P12 record details on the extent and location of the faults in an appropriate format, including as appropriate, drawing valid conclusions on the options for rectifying the fault and the changes required to possession and protection arrangements
P13 address problems within your control and report unresolved issues
Knowledge and Understanding
You need to know and understand:
K1 the relevant health and safety regulations, directives, guidelines, and safe working practices and procedures defined by your organisation, as appropriate to the activity and your working area
K2 the relevant railway possession and protection arrangements for the work site and equipment to provide a safe system of work and how to check these have been implemented
K3 how to locate and access the site
K4 how to secure the system prior to fault finding activities taking place
K5 the activities which may compromise system functionality and integrity including the operational constraints to carrying out diagnostic activities
K6 how to identify, evaluate and respond to influencing factors whilst carrying out the tests/checks, including environmental factors, site conditions and working on an operational railway
K7 the isolation and lock-off procedure or permit-to-work procedure that applies to the system (such as electrical isolation, locking off switchgear, placing of warning notices, proving the isolation has been achieved and secured)
K8 the classification of different voltage levels and the authority requirements for working on them
K9 what constitutes a hazardous voltage/current and how to recognise victims of electric shock
K10 how to reduce the risks of an electric shock (such as insulated tools, rubber mating and isolating transformers)
K11 the importance of wearing protective clothing and other appropriate safety equipment (PPE) during the testing activities
K12 the hazards associated with carrying out signalling diagnostic activities (such as stored energy, radio frequency radiation, electrical supplies, electrical/electronic interfaces, using damaged or ill-maintained tools and equipment, not following laid-down diagnostic procedures), and how to minimise these and mitigate any risks
K13 how to source and interpret engineering diagrams, related specification approved manuals and other related information such as previous diagnostic information
K14 the principles of operation of the equipment to be diagnosed
K15 how to source and evaluate information relating to the fault, including as appropriate, eye witness accounts, re-occurring faults
K16 the types of fault diagnostic aids available and how to use them
K17 the relevant methods and techniques for fault finding
K18 how to locate and identify the equipment to be tested and/or checked
K19 your organisation's procedures for failure investigation
K20 what constitutes a fault and/or defect in signalling equipment
K21 how to assess the potential risks arising from faults and/or defect and the implications involved
K22 what operational constraints could occur whilst carrying out fault finding activities
K23 the procedures and precautions to be adopted to eliminate electrostatic discharge (ESD) hazards when working with and handling electronic devices
K24 what activities could compromise the system functionality and integrity
K25 the methods and techniques for data diagnostic analysis relevant to the equipment
K26 how to select and use the correct tools and test equipment to ensure true and accurate measurements are obtained and confirm that they are calibrated
K27 your organisation's procedures for the use, care and control of inspection tools and equipment
K28 the importance of calibrating tools and test equipment
K29 how to interpret and analyse information from measuring instruments, including as appropriate, performing calculations
K30 how to use test equipment so as to ensure true and accurate measurements are taken
K31 your organisation's procedures for the control of faults and modifications
K32 the relevant reporting lines and procedures that are approved by your organisation
K33 the limits of your own authority and responsibility and those of others involved
Scope/range
Scope Performance
Types of health and safety legislation, regulations and safe working practices and procedures, as applicable to the work location and activities, could include:
- your organisation's safety management system
- control of substances hazardous to health
- safe work plans
- track access restrictions
- track work instructions
- track possession
- task risk control sheets
- current rule book
- regulations for working under OLE and in the vicinity of DC lines (where appropriate)
- equipment disconnections
- manual handling
- reporting of injuries, diseases and dangerous occurrences
- safety signage legal requirements
- PPE
Site locations could include:
- trackside
- internal (such as signal box, equipment room)
- areas to which the public have access
- confined spaces elevated structures
Types of signalling equipment on which faults may be diagnosed could include:
- points
- train control (such as signals, balises or other method of authorising train movements)
- train detection (such as track circuits or axle counters)
- power supplies
- ETCS
- other industry specific signalling equipment
Types of approved/calibrated tools and equipment used to determine the fault location, as applicable to the equipment being tested, will include:
- calibrated hand tools
- un-calibrated hand tools
- calibrated test leads/loads
- computerised test equipment
- test recording equipment
- other specific signalling test equipment
Sources of fault diagnosis evidence could include:
- the person or operator who reported the fault
- equipment self-diagnosis
- test instrument measurements
- recording devices
- sensory input (such as sight, sound, smell, touch)
- equipment records
- circuit meters equipment outputs
Fault diagnostic techniques could include:
- half-split technique
- input/output technique
- injection and sampling
- six point technique
- emergent sequence
- unit substitution
- function/performance testing
- equipment self-diagnostics
Types of diagnostic aids used could include:
- investigation guides
- logic diagrams
- fault analysis charts (such as fault trees)
- flow charts or algorithms
- manufacturers' manuals
- probability charts/reports
- troubleshooting guides
- computer-aided test equipment electronic aids
Fault diagnosis activities may need to be carried out in accordance with the following:
- infrastructure guidelines and standard operating procedures
- equipment manufacturer's documents
- BS, ISO and/or BS EN standards
- authorised test plan
- investigation guide other industry specific signalling standards/specifications
Types of diagnostic records that need to be completed and passed to the appropriate people could include:
- job card
- fault log and action report
- company reporting procedures
- other industry specific test records