6 OHM Track Resistor T HR SC SP. Specification. Version 1.0. Issued date: 09 July Important Warning

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1 Specification Important Warning This document is one of a set of standards developed solely and specifically for use on public transport assets which are vested in or owned, managed, controlled, commissioned or funded by the NSW Government, a NSW Government agency or a Transport Agency (as defined in the Asset Standards Authority Charter). It is not suitable for any other purpose. You must not use or adapt it or rely upon it in any way unless you are authorised in writing to do so by a relevant NSW Government agency. If this document forms part of a contract with, or is a condition of approval by a NSW Government agency, use of the document is subject to the terms of the contract or approval. This document may not be current. Current standards are available for download from the Asset Standards Authority website at State of NSW through Transport for NSW

2 Standard governance Owner: Authoriser: Approver: Lead Signals and Control Systems Engineer, Asset Standards Authority Principal Manager Network Standards and Services, Asset Standards Authority Director, Asset Standards Authority on behalf of the ASA Configuration Control Board Document history Version Summary of Changes 1.0 First issue. For queries regarding this document, please the ASA at or visit State of NSW through Transport for NSW

3 Preface The Asset Standards Authority (ASA) is an independent unit within Transport for NSW (TfNSW) and is the network design and standards authority for defined NSW transport assets. The ASA is responsible for developing engineering governance frameworks to support industry delivery in the assurance of design, safety, integrity, construction, and commissioning of transport assets for the whole asset life cycle. In order to achieve this, the ASA effectively discharges obligations as the authority for various technical, process, and planning matters across the asset life cycle. The ASA collaborates with industry using stakeholder engagement activities to assist in achieving its mission. These activities help align the ASA to broader government expectations of making it clearer, simpler, and more attractive to do business within the NSW transport industry, allowing the supply chain to deliver safe, efficient, and competent transport services. The ASA develops, maintains, controls, and publishes a suite of standards and other documentation for transport assets of TfNSW. Further, the ASA ensures that these standards are performance-based to create opportunities for innovation and improve access to a broader competitive supply chain. This document describes the requirements for ac track resistors used in railway signalling applications. This document has been developed from the RailCorp document SPG OHM Track Resistor, Version 1.1 and has been reviewed and approved by the Asset Standards Authority. This ASA specification supersedes RailCorp document SPG 1040 and is a first issue. State of NSW through Transport for NSW Page 3 of 7

4 Table of contents 1. Introduction Purpose Scope Application Reference documents Terms and definitions Requirements Life expectancy Rating Adjustment requirements Termination of wiring Wiring Insulation Dimensions Mounting Unit labelling... 7 State of NSW through Transport for NSW Page 4 of 7

5 1. Introduction This equipment specification details the requirements for the design and fabrication of a variable resistor module to be used in a track circuit application. As such they are known colloquially as ac track resistors. The resistor module is comprised of a variable resistor/s, adjustment slider, terminals and mounting frame. The resistor module may be used in other non-electronic railway signalling applications. 2. Purpose 2.1. Scope The purpose of this specification is to detail the requirements of a variable resistor module designed to fit within a standard footprint on an equipment rack inside a signalling equipment location. The variable resistor module forms part of a feed arrangement for single and double Rail 50 Hz track circuits. While the primary use for this module is intended for track circuits, it may be used for other non-electronic Railway Signalling applications. The scope of this document covers the design, fabrication and assembly aspects only. It does not extend to the application of where and how these resistors are intended to be deployed nor does it address any installation requirements such as allowances for heat dissipation Application The intended use of this document is to detail the design, fabrication and assembly requirements for a 6 Ohm variable track resistor module. As such the intended audience for this document are those in the design, manufacture and supply of electrical modules made from standard and some bespoke design elements. 3. Reference documents No other standards or specifications are referenced in this document 4. Terms and definitions track resistor a variable 6 Ohm resistor used in 50Hz single and double rail track circuits. The role of this resistor is to control the phase angle to a phase sensitive vane relay. While its primary use is in track circuits, it may be used for other railway signalling applications. State of NSW through Transport for NSW Page 5 of 7

6 5. Requirements A high level of workmanship and quality is necessary to ensure reliability and a preference will be made for units with conservative ratings. The resistors shall be wound on grooved ceramic formers to ensure linearity of winding. All materials used in the construction of these units should be suitably treated against corrosion and shall not be affected by heat or water or promote fungal growths Life expectancy The design of the resistor module shall be such so as to achieve a minimum life expectancy of 30 years. 6. Rating The nominal value of the resistors shall be 6 ohm continuously adjustable down to 0.25 ohms. The use of two adjustable resistors is permitted. The resistors shall have a capability of passing 20 A through any leg of the resistor at any value of resistance. 7. Adjustment requirements The adjustment method shall be simple and should not cause hot spots on the adjuster at full load because of small contact area. A standard resistor adjustment band is not considered suitable because of the frequency of use and reliability required. Contact pressure of the adjuster for the resistor should not be affected by vibration which will be prevalent during the service life of the unit. Adjustment of resistor in service should not cause injury to the user as a result of excessive heat. A terminating point should be made available in the adjuster for terminating a cable connection. 8. Termination of wiring Terminations on the resistor should be well clear of all metal work and should not be positioned such that wiring could be entangled or suffer heat damage. Terminals for connecting to the resistor should be nickel plated brass M6 metric coarse threaded studs nuts, which shall be firmly secured using locking nuts. A connection stud shall be made available on the adjustment leg. State of NSW through Transport for NSW Page 6 of 7

7 9. Wiring All wiring shall be suitably rated as fire resistant and should be suitably terminated on non-insulated lugs and laid between nickel plated brass washers. Soldered connections anywhere on the unit are not permitted. Indent crimping is not an approved method of terminating crimp lugs. 10. Insulation Mounting and termination of the resistors shall be free from earth. Wiring terminations shall be insulated from the frame of the unit. Any insulation used within the module shall take into account the heat rise of the resistors themselves and degradation due to long term heat exposure. 11. Dimensions The overall dimensions should not exceed 200 mm long, 150 mm wide and 120 mm high Mounting Mounting of the units should be on centres of 115 mm vertical and 105 mm horizontal with 7 mm mounting holes. 12. Unit labelling The manufacturer should have an identifying nameplate which shall be made of a non-corrosive material not affected by heat firmly and permanently affixed to the unit. The following information is required to appear on the nameplate: manufacturers name rating of the unit and its resistance serial number including month and year of manufacture of the unit packaging of the unit should be individual and the following information should be included on the outside of the case: ᴑ ᴑ the order number description of the item, for example, 6 ohm track resistor State of NSW through Transport for NSW Page 7 of 7