Electronic Interlocking (EI) Requirements - PDF

Section 4: Electronic Interlocking (EI) 21.4.1 Essential Requirements of Electronic Interlocking (a) Electronic Interlocking System shall be approved type and shall conform to latest approved specification. (b) Electronic Interlocking System shall have the highest level of...

Section 4: Electronic Interlocking (EI) 21.4.1 Essential Requirements of Electronic Interlocking (a) Electronic Interlocking System shall be approved type and shall conform to latest approved specification. (b) Electronic Interlocking System shall have the highest level of safety integrity as stipulated. (c) Electronic Interlocking System shall be suitable for working on Electrified and Non-Electrified sections. (d) Electronic Interlocking System Installation shall be of Route setting type using Dropdown menu Or Entry/Exit control with a facility for individual operation of points. (e) Signalling and interlocking arrangements for the Yard shall be in accordance with the approved Signal Interlocking plan (SIP) and Control Table. (f) Electronic interlocking system shall be capable of working with Control Panel or/and Control Terminal. (g) Electronic Interlocking system shall have adequate built-in redundancy as per approved specification. (h) Provisions given in Sections 1, 2 given above are generally applicable for Electronic Interlocking also. 21.4.2 Control Terminal (Video Display Unit (VDU)) (a) Same requirements given in Para 21.1.1, 21.1.2 shall apply for existing Control Panels (where provided) for Electronic Interlocking (E.I) installations. Control Panels shall not be used in future Electronic Interlocking installations. (b) Control Terminal/multiple Control Terminals shall be of appropriate size to display layout of the Yard in well-proportioned dimensions and shall display all functions clearly distinguishable. Normally Control Terminal/multiple Control Terminals shall be provided in redundant mode. (c) Video Display indications on Control Terminal shall conform to Control Panel indications as covered in Para 21.1.4 or other approved type. (d) Operation of Signals, Points and other Controls such as Gate, Crank handle, Siding, Slot etc., shall be carried out through appropriate dropdown menus or other approved means. (e) Control Terminal shall have suitable protection facility against unauthorized operation which may be provided by physical „SM Key‟ in a separate box and key contacts are taken to pick up two separate „SM Key‟ relays in relay room for redundancy purpose. These relay contacts are taken as input through two different input cards preferable in different OC‟s and „SM Key IN‟ bit shall be made by their parallel proving inside E.I. Chapter 21: Relay & Electronic Interlocking Page 455 of 530  (f) All Emergency operations shall be two-step process protected against unintended operations. (g) Only non-resettable counters shall be provided while working with Control Panel or Control Terminal. (h) Control Terminal shall have provision for Signal, Point and Line Block Collars equivalent of Control Panel in the form of individual „Block‟ & „Un- Block‟ feature which shall remain effective even during changeover from one Control Terminal to other Control Terminal. „All Un Block‟ option shall be provided while E.I starts up to un-block all signals, points & lines after a time delay of at least 120 seconds. SM‟s key shall be required for unblocking of a function whereas no SM‟s key required for blocking. There should not be any automatic unblocking of functions. Blocking of a function shall be indicated on Control Terminal by different mark or colour over the concerned function. (i) Where Control Panel and Control Terminal are provided, it shall be possible to switchover the controls from Control Panel to Control Terminal and vice-versa, and where two Control Terminals are provided, it shall be possible to switch the controls from one Control Terminal to other Control Terminal through suitable means by either manual switch or password. (j) Indication that E.I system is healthy shall be displayed on the Control Panel using a blinking green LED or blinking green indicator on Control Terminal. (k) Operation of points shall be possible only, when the interlocking is free and relevant point track circuit is clear. Emergency operations provided when point zone track circuit fails and after line verification from site by traffic personnel, it shall be possible to operate the concerned point by inserting an emergency key in a separate box provided interlocking is free. Each such operation shall be recorded on a non-resettable counter. (l) Each „Normal‟ or „Reverse‟ operation of point shall be controlled through two output relays derived from two output bits should be from different output cards of E.I. (m) Last controlled position of points shall be available by using latch relay in point control circuits. (n) Mid stroke point reversal preventing feature shall be provided to prevent starting of operation when the point is under operation or tried for other position during mid stroke. (o) When embedded block working in Electronic Interlocking is used, all indications like TGT, TCF, LC etc required for block working shall also be displayed 21.4.3 Interface with Electronic Interlocking (a) Interface between Control Panel, Video Display Unit and Electronic Interlocking system shall be of approved type. (b) Interface of Points, Signals, Track Circuits and Controls such as Crank Handle, LC Gate, Siding, Slot etc., with Electronic Interlocking System shall be through Relays of approved type or through any Electronic Modules of approved type conforming to approved specification. Interface with E.I of adjacent station, Digital axle counter shall be of approved type. Chapter 21: Relay & Electronic Interlocking Page 456 of 530  (c) Interface between external data logging equipment and Electronic Interlocking system shall conform to approved specification. (d) Electronic Interlocking System shall be capable of being controlled and monitored from a either centralized location or distributed locations as per requirement at site. (e) It shall be possible to network the Electronic Interlocking Systems for diagnostic function to a centralized location. (f) Electronic Interlocking system may be capable of being networked with other systems for the purpose of centralized control and monitoring. 21.4.4 Interlocking & Circuit Requirements (a) Interlocking application logic (site specific data) requirements for the E.I system shall be as per interlocking principles stipulated for Relay Interlocking and Standard Circuits for Electronic Interlocking. (b) It shall be possible to modify application logic for yard remodeling or change in interlocking using approved type of user interface. (Note: For Standardised Typical Circuits of Electronic Interlocking, may refer to http://10.100.2.19/signal/policy/uniform_circuit_diagram/Report%20SS%20155 %202019%20(std%20ckts%20of%20EI)%20Booklet%20print.pdf) 21.4.5 Powering up of Electronic Interlocking (a) Electronic Interlocking system shall drive all the relevant signals to the most restrictive aspects whenever internal failure of any nature arises or when Electronic Interlocking system is powered up or during shutdown. (b) After powering up of Electronic Interlocking the system shall block all signals and other operations. After verification of safety functions by Electronic Interlocking system, this blocking shall be released after a delay of at least 120 seconds. 21.4.6 Configuration of Electronic Interlocking a) Electronic Interlocking system shall have hot-standby arrangement and changeover from one system to other systems shall not interrupt status of signalling. b) Electronic Interlocking system shall be of either Centralised or Distributed type as per approved specification and as per policy directives. c) In case of Distributed configurations, redundancy with route diversity in OFC communication media and power supply system shall be provided for linking the subsystems. d) Electronic Interlocking system in any configuration shall have time synchronisation. Chapter 21: Relay & Electronic Interlocking Page 457 of 530 21.4.7 Version Control of Softwares of Electronic Interlocking (a) Version of the Generic System software and hardware shall be approved and controlled by authority competent to approve the Electronic Interlocking system and its specifications. (b) Version and checksum of the Application logic (station specific logic) shall be unique for the installation and shall be approved by the authority competent to approve the circuit diagrams. Corresponding Checksum shall be recorded and controlled by the same authority. (c) Version number and Checksum shall change whenever any modifications are carried out to the Application logic (site specific logic). (d) A proper record of Checksums shall be maintained at Station, Divisional Headquarters and Zonal Headquarters as a part of completion circuit diagrams. Section 5: Installation & Testing of Electronic Interlocking 21.5.1 Installation of Electronic Interlocking (a) Installation of Electronic Interlocking system shall be done as per approved guidelines and technical advisory notes issued from time to time. (b) Application logic (site specific logic) shall be verified for safety and functionality by carrying out exhaustive safety and functionality tests by officers authorized by PCSTE. (c) Only approved application logic with specified checksum shall be used in the E.I system and this data and checksum shall be version controlled and preserved by the Railways. (d) Electronic Interlocking is required to be provided in dust proof cabinets of approved type having transparent front door. (e) Interface Relays, where provided, shall be of approved type and contacts should be paralleled as far as possible for better reliability. (f) Wherever possible, the spare input/outputs shall also be wired from E.I cards up to Wago terminals for ease of carrying out future alterations. (g) The input and output cables of E.I shall be twisted to minimize EMI & EMC effect. (h) Electronic Interlocking system shall be installed closer to Operator Room, preferably adjacent room. Track crossing should be avoided between main E.I system and operator room. (i) The Electronic Interlocking room shall be provided with tiles or similar arrangements on floor and walls to avoid periodic painting of walls and resultant dust. Chapter 21: Relay & Electronic Interlocking Page 458 of 530