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SOUTH AFRICAN QUALIFICATIONS AUTHORITY 
REGISTERED UNIT STANDARD: 

Demonstrate an understanding of the principles of mechanical railway signalling 
SAQA US ID UNIT STANDARD TITLE
116846  Demonstrate an understanding of the principles of mechanical railway signalling 
ORIGINATOR
SGB Electrical Engineering & Construction 
PRIMARY OR DELEGATED QUALITY ASSURANCE FUNCTIONARY
-  
FIELD SUBFIELD
Field 12 - Physical Planning and Construction Electrical Infrastructure Construction 
ABET BAND UNIT STANDARD TYPE PRE-2009 NQF LEVEL NQF LEVEL CREDITS
Undefined  Regular  Level 2  NQF Level 02 
REGISTRATION STATUS REGISTRATION START DATE REGISTRATION END DATE SAQA DECISION NUMBER
Reregistered  2018-07-01  2023-06-30  SAQA 06120/18 
LAST DATE FOR ENROLMENT LAST DATE FOR ACHIEVEMENT
2024-06-30   2027-06-30  

In all of the tables in this document, both the pre-2009 NQF Level and the NQF Level is shown. In the text (purpose statements, qualification rules, etc), any references to NQF Levels are to the pre-2009 levels unless specifically stated otherwise.  

This unit standard does not replace any other unit standard and is not replaced by any other unit standard. 

PURPOSE OF THE UNIT STANDARD 
A learner credited with this unit standard will be able to identify and explain the purpose and operation of the equipment that forms the fundamental elements of mechanical railway signalling. Understanding these signalling elements and their relationships will prepare the learner for a continuum of learning in the field of signalling. This will give the learner a clear understanding of how a reliable railway signalling system contributes to safe and efficient train operations, which results in effective rail transportation. 

LEARNING ASSUMED TO BE IN PLACE AND RECOGNITION OF PRIOR LEARNING 
  • Communication NQF Level 1
  • Mathematics NQF Level 1 

  • UNIT STANDARD RANGE 
    The credit value assigned to this unit standard is appropriate because performance must be carried out:
    1. In a controlled environment.
    2. Within a specific time.
    3. At a field site or in a workshop.
    4. Under simulated conditions.

    This standard includes the following elements of mechanical signalling:
    1. Semaphore signals
    2. Mechanical points
    3. Derailers
    4. Mechanical detector boxes
    5. Mechanical lever frames
    6. Points indicators. 

    Specific Outcomes and Assessment Criteria: 

    SPECIFIC OUTCOME 1 
    Demonstrate an understanding of mechanical points operation. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The mechanical components of the points can be identified by name. 

    ASSESSMENT CRITERION 2 
    The operation of the mechanical points movement box and associated cam action is explained according to mechanical handbook. 

    ASSESSMENT CRITERION 3 
    The operation of the associated points detection is explained according to mechanical handbook. 

    ASSESSMENT CRITERION 4 
    The purpose and operation of the following are explained according to mechanical handbook:
  • The mechanical detector box
  • The lock bar
  • The facing-point lock and facing-point bolt. 

  • ASSESSMENT CRITERION 5 
    The function and operation of a derailer coupled to a ground indicator is explained according to mechanical handbook. 

    SPECIFIC OUTCOME 2 
    Demonstrate an understanding of the mechanical signal operation. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The components of the mechanical signal can be identified by name. 

    ASSESSMENT CRITERION 2 
    The various types of signal arms are identified correctly and their purpose and functions are explained. 

    ASSESSMENT CRITERION 3 
    The operation of the signal arms is explained according to mechanical handbook. 

    ASSESSMENT CRITERION 4 
    The function and operation of the following equipment can be explained:
  • A single-wire and double-wire system
  • A mechanical signal replacer
  • A semaphore signal repeater 

  • ASSESSMENT CRITERION 5 
    The differences in observations of signals during the day time and night time can be explained. 

    SPECIFIC OUTCOME 3 
    Demonstrate an understanding of a mechanical interlocking system. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The components of the mechanical lever frame can be identified by name. 

    ASSESSMENT CRITERION 2 
    The reasons for using the following can be explained:
  • The interlocking on the signals and points
  • The use of back stroke locking on home signals
  • The switching out of the lever frame 

  • ASSESSMENT CRITERION 3 
    The correct sequence and method of operating the mechanical lever frame is demonstrated. 

    SPECIFIC OUTCOME 4 
    Demonstrate an understanding of one-way and two-way points indicators. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The mechanical operation of the signal arms can be explained. 

    ASSESSMENT CRITERION 2 
    The components of the points indicator can be identified. 

    ASSESSMENT CRITERION 3 
    The method of operating the points indicator is demonstrated. 

    ASSESSMENT CRITERION 4 
    The disk arms of the points indicator can be identified. 

    ASSESSMENT CRITERION 5 
    The purpose and functions of the points indicators can be explained. 


    UNIT STANDARD ACCREDITATION AND MODERATION OPTIONS 
    1. An individual wishing to be assessed against this unit standard may apply to an assessment agency, assessor or provider institution that has been accredited by the relevant ETQA.
    2. Anyone assessing a learner against this unit standard must be registered as an assessor with the relevant ETQA.
    3. Any institution offering learning that will enable achievement of this unit standard must be registered and accredited as a provider with the relevant ETQA as prescribed.
    4. Moderation of assessment will be done by the relevant ETQA as prescribed.
    5. Anyone assessing a learner against this unit standard must be certified as competent against this unit standard and registered as an assessor to assess this unit standard. 

    UNIT STANDARD ESSENTIAL EMBEDDED KNOWLEDGE 
    The learners can understand and explain the following related to the application and function of the equipment that forms the elements of mechanical railway signalling:
  • The control and operation of mechanical points and derailer
  • The control and operation of mechanical signals and detectors
  • The identification and observation of semaphore signals
  • Functions of mechanical signals, points and derailer
  • Functions of mechanical interlocking
  • Relationships between signalling elements and interlocking
  • Philosophy of the principle of "failure to safety" 

  • UNIT STANDARD DEVELOPMENTAL OUTCOME 
    N/A 

    UNIT STANDARD LINKAGES 
    N/A 


    Critical Cross-field Outcomes (CCFO): 

    UNIT STANDARD CCFO ORGANISING 
    Self-organisation and self-management:

    A learner can organise and manage himself by understanding the principles of mechanical railway signalling. 

    UNIT STANDARD CCFO COLLECTING 
    Information evaluation:

    Learners can interpret and evaluate the positions of the various railway signalling elements on the station diagram. 

    UNIT STANDARD CCFO DEMONSTRATING 
    Inter-relatedness of systems:

    Learners can understand the relationship between signalling elements in a mechanical railway signalling environment. 

    UNIT STANDARD CCFO CONTRIBUTING 
    Learner and societal development:

    Learners can understand the importance of:
  • Safety in the workplace as well as in the whole environment
  • Their responsibility for the safety and well-being of fellow-workers and society at large 

  • UNIT STANDARD ASSESSOR CRITERIA 
    N/A 

    REREGISTRATION HISTORY 
    As per the SAQA Board decision/s at that time, this unit standard was Reregistered in 2012; 2015. 

    UNIT STANDARD NOTES 
    Assessment Process:

    Assessment Methods:
    1. Written tests.
    2. Practical test.
    3. Oral questioning.
    4. Observation of practical task execution.
    5. Simulation.
    6. Role-play/structured classroom discussions and oral tests.
    7. Practical verification against specifications.

    These methods must be selected carefully based on the purpose of the assessment (for example, the written method could be used to assess knowledge or on-the-job demonstration for practical competence). The assessment must integrate a number of different methods (no less than three of those detailed above) in order to give the assessor reliable and valid proof of competence and evidence of required attitudes.

    The following may be used to supplement the above minimum assessment methods:

    Valid, reliable and authentic evidence (presented as a portfolio of evidence) from past achievements and experience may serve to supplement the assessment of applied competence. The portfolio should include inter alias:

    1. Written statements from persons (e.g. current and/or previous employer, colleague, peer, manager, external customers) confirming competence of the learner.
    2. Relevant certificates or awards.
    3. Previous assessment records.
    4. Logbook or register stating evidence of performance.

    Values:

    In addition, the following values should be demonstrated:
  • Safety consciousness
  • Responsibility
  • Integrity
  • Quality consciousness
  • Time consciousness
  • Sobriety

    Supplementary Information:

    Terminology:

    Plan refers to a drawing or diagram.
    Logbook refers to evidence of training and job performance.

    Certification:

    The learner will be certified as competent when the criteria specified in the specific outcomes of this unit standard have been met successfully.

    Credits:

    Total hours required by the learner to achieve the required outcomes:

    Activity and number of hours:
  • Theory: 40 hours
  • Practical: 12 hours
  • Self-directed learning: 3 hours
  • On-the-job learning: 6 hours
  • Assessment: 3 hours
    Total: 64 hours

    Credits achieved: 6 

  • QUALIFICATIONS UTILISING THIS UNIT STANDARD: 
      ID QUALIFICATION TITLE PRE-2009 NQF LEVEL NQF LEVEL STATUS END DATE PRIMARY OR DELEGATED QA FUNCTIONARY
    Core  49066   National Certificate: Railway Signalling: Installation and Scheduled Maintenance of Equipment  Level 3  NQF Level 03  Reregistered  2023-06-30  TETA 


    PROVIDERS CURRENTLY ACCREDITED TO OFFER THIS UNIT STANDARD: 
    This information shows the current accreditations (i.e. those not past their accreditation end dates), and is the most complete record available to SAQA as of today. Some Primary or Delegated Quality Assurance Functionaries have a lag in their recording systems for provider accreditation, in turn leading to a lag in notifying SAQA of all the providers that they have accredited to offer qualifications and unit standards, as well as any extensions to accreditation end dates. The relevant Primary or Delegated Quality Assurance Functionary should be notified if a record appears to be missing from here.
     
    NONE 



    All qualifications and part qualifications registered on the National Qualifications Framework are public property. Thus the only payment that can be made for them is for service and reproduction. It is illegal to sell this material for profit. If the material is reproduced or quoted, the South African Qualifications Authority (SAQA) should be acknowledged as the source.