Carry out fault diagnosis on traction and rolling stock communication-electronic systems
Overview
This standard identifies the competencies you need to carry out efficient and effective fault diagnosis on traction and rolling stock communication-electronic systems, in accordance with approved procedures. You will be required to diagnose faults on a range of communication-electronic systems, sub-systems or assemblies at the line replacement unit (LRU) level. You will be expected to use a variety of fault diagnosis methods and techniques, and to utilise a number of diagnostic aids and equipment. From the evidence gained, you will be expected to identify the fault and its probable cause, and to suggest appropriate action to remedy the problem. The term traction and rolling stock used in this standard applies to passenger, freight and on-track machines (OTM).
Where it is relevant these standards also apply to traction and rolling stock that has been fitted with the European Train Control System (ETCS).
Your responsibilities will require you to comply with organisational policy and procedures for the fault diagnostic activities undertaken, and to report any problems with these activities or the tools and equipment used that you cannot personally resolve, or that are outside your permitted authority, to the relevant people. You will be expected to work with minimal supervision, taking personal responsibility for your own actions and for the quality and accuracy of the work that you carry out.
Your underpinning knowledge will provide a good understanding of your work and will provide an informed approach to applying fault diagnosis procedures on traction and rolling stock communication-electronic systems. You will understand the various fault diagnosis methods and techniques used and their application. You will also know how to apply and interpret information obtained from diagnostic aids and equipment, in adequate depth to provide a sound basis for carrying out the activities and identifying faults or conditions that are outside the required specification.
You will understand the safety precautions required when carrying out fault diagnosis activities, especially those for isolating the equipment and for taking the necessary safeguards to protect yourself against direct and indirect electric shock. You will be required to demonstrate safe working practices throughout and will understand the responsibility you owe to yourself and others in the workplace.
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 review and use all relevant information on the symptoms and problems associated with the products or assets
P3 investigate and establish the causes of the faults
P4 select, use and apply diagnostic techniques, tools and aids to locate faults
P5 complete the fault diagnosis within the agreed time and inform the appropriate people when this cannot be achieved
P6 determine the implications of the fault for other work and for safety considerations
P7 use the evidence gained to draw valid conclusions about the nature and probable cause of the fault
P8 record details on the extent and location of the faults in an appropriate format
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 isolation and lock-off procedure or permit-to-work procedure that applies to the system being worked on (such as electrical isolation, locking off switchgear, placing of maintenance warning notices, proving the isolation has been achieved and secured)
K3 what constitutes a hazardous voltage/current and how to recognise victims of electric shock
K4 how to reduce the risks of an electric shock (such as insulated tools, rubber matting and isolating transformers)
K5 the classification of different voltage levels and the authority requirements for working on them
K6 the importance of wearing protective clothing and other appropriate safety equipment (PPE) during the fault diagnostic process
K7 hazards associated with carrying out fault diagnosis on communication- electronic systems (such as high voltages/currents, stored capacitive/inductive energy, radio frequencies, misuse of tools), and how to minimise them and reduce any risks
K8 the procedures and precautions to be adopted to eliminate electrostatic discharge (ESD) hazards
K9 the procedure to be adopted to establish background evidence of a fault
K10 how to evaluate the various types of information available for fault diagnosis
K11 how to use the various aids and reports available for fault diagnosis
K12 how to use various items of fault diagnostic equipment to investigate the problem
K13 the various fault finding techniques that can be used, and how they are applied (such as half-split, input-to-output, emergent sequence, six point technique, function testing, unit substitution, injection and sampling techniques, and equipment self-diagnostics)
K14 how to evaluate sensory conditions (sight, smell, sound or touch)
K15 how to analyse evidence and evaluate possible characteristics and causes of specific faults or problems
K16 how to relate previous reports/records of similar fault conditions
K17 the care, handling and application of electronic test instruments (such as multimeters, logic probes, oscilloscopes)
K18 how to determine the calibration state of the equipment, and the actions to be taken if equipment is out of calibration
K19 how to ensure that the equipment used is free from damage or defect
K20 how to obtain and interpret drawings, circuit diagrams, physical layouts, charts, specifications, manufacturers' manuals, history/maintenance reports, electronic/electrical symbols, and other documentation needed in the maintenance process
K21 the principles of how communication-electronic or associated systems function and interact with each other such as ETCS, AWS, or TPWS
K22 how sub-systems and assemblies function within the system
K23 the purpose of each LRU within a given system
K24 how to evaluate the risk to yourself and others, and the effects the fault could have on the overall process
K25 how to prepare and produce a risk analysis report, where appropriate
K26 how to complete the necessary paperwork or take follow-up action, which satisfies the company policy on concluding fault diagnosis
K27 the extent of your own responsibility and to whom you should report if you have problems that you cannot resolve
Scope/range
Scope Performance
During the fault diagnostic activity, individuals will:
- plan the fault diagnosis prior to beginning the work
- obtain and use the correct issue of company and/or manufacturer's drawings and maintenance documentation as well as the correct version of any maintenance software tools required
- adhere to procedures or systems in place for risk assessment, control of substances, personal protective equipment and other relevant safety regulations and procedures to realise a safe system of work
- ensure the safe isolation of equipment
- provide and maintain safe access and working arrangements for the fault finding/maintenance area
- warn others in the maintenance area if they are at risk of injury from the system being tested
- carry out the fault diagnosis activities using appropriate procedures
- collect equipment fault diagnosis evidence from live and isolated circuits
- disconnect or isolate components or parts of circuits, when appropriate, to confirm diagnosis
- identify the fault and determine appropriate corrective action
- dispose of waste items to comply with environmental protection guidelines and ensure the work area remains safe
Types of communication electronic systems, sub-systems or assemblies, on which fault diagnosis may be carried out to LRU level, include:
- transmitters
- transceivers
- receivers
- aerial systems
- radar systems
- staff communication systems (such as GSMR, PA, cab to cab)
- train control systems (such as AWS, ATP, TPWS, ETCS)
- data transmission lines (such as fibre optics, coaxial, baluns, twin wire)
- display systems (such as crew and passenger information)
- driver-machine interface
- optical systems (such as CCTV)
- built-in test equipment
- data network systems (such as LANs, WANs)
- data network interfaces (such as switches, router, bridging networks)
- any other identifiable electronic system, sub-system or assemblies to Line Replaceable Unit (LRU) level Associated equipment
- environmental control systems (such as temperature, alarms, fire protection, fire suppression)
- electromechanical systems (such as servos, motors, relays, complex switches)
- power generation systems (such as AC/DC generators, batteries)
- power distribution systems (such as single phase/3-phase distribution panels, shore connections)
- traction supply control systems (such as inverters, rectifiers, regenerative braking)
- monitoring systems (such as On Train Data Recorder (OTDR))
- hybrid systems (such as ADC, DAC)
Sources of fault diagnosis evidence include:
- person or operator who reported the fault
- recording devices
- test instrument measurements
- sensory (such as sight, sound, smell, touch)
- equipment records
- circuit meters
- equipment self-diagnostics
Fault-diagnostic techniques carried out could include the following:
- half-split
- injection and sampling
- emergent sequence
- function/performance testing
- six point technique
- unit substitution
- equipment self-diagnostics
Diagnostic aids used could include:
- logic diagrams
- fault analysis charts
- flow charts or algorithms
- manufacturers' manuals
- probability charts/reports
- troubleshooting guides
- computer-aided test equipment
- electronic aids
Types of fault diagnostic procedures could include:
- inspection
- operation
- measurement
Types of test equipment, used to aid fault diagnosis, could include the following:
- oscilloscope
- multimeter
- current tracer
- logic probe
- signal generator
- built in test equipment (BITE)
- computer aided diagnostic equipment
- special-purpose testing equipment
- automatic test equipment
- other specific test equipment
Breakdown categories may include:
- intermittent action/system failure
- complete breakdown
- partial failure or reduced performance
Methods for recording the outcome of the fault diagnosis could include:
- step-by-step analytical reports
- corrective action reports
- preventative maintenance log/reports
- company-specific reporting procedures