Synthesis of safety functions for railway automation and telemechanics systems Michael N. Vasilenko, Peter A. Vasilenko, Valentin A. Hodakovskij Department of "Automation and telemechanics on railways" Petersburg State Transport University Emperor Alexander I Abstract The language of description of track objects (LTO) is a powerful tool for working with electronic technical documentation of railway automation and telemechanics. The principles of construction, areas of application, syntax and semantics of LTO were described in a previously published article [1,2]. The software implementation of this language in the object format of technical documentation in the XML extensible markup language is described in [3]. The analysis of the systems of railway automation and telemechanics from the point of view of functional safety, based on the application of the logical principles of the language of track objects. An approach is given for the formation of a complete set of safety functions for station automation systems, based on the technical documentation of the railway. Keywords electronic technical documentation, language for describing track objects, schematic plan of the station, dependency table, letters, words and sentences of LTO, safety functions, train traffic safety 1. Introduction 2. Basic set of security features The principles of constructing the language for The theory of synthesis of safe systems describing path objects (LTO) and its application of railway automation and telemechanics areas, syntax and semantics are described in [1,2]. [3] (RATS) provides a solution to two main describes the software implementation of LTO in the problems [4-6]: branch format of technical documentation (IFTD) used 1. Automation of train traffic control. in computer-aided design and technical documentation 2. Ensuring the safety of train traffic. systems and provides examples of grammatical To ensure the safety of train traffic, constructions of LTO in the extensible markup XML scientists of the Department of Automation and language for a schematic plan of a station (SSP) and a Telemechanics on Railways of the St. table of interdependence of arrows and signals (TD). Petersburg State University of Railways of This article is devoted to the formation of a complete Emperor Alexander 1 developed a theory of set of safety functions for ATS using the basic safety [4-6] and determined the conditions for conditions defined in the theory of construction of safe systems ensuring functional safety, the RATS. fulfillment of which is necessary for organizing The algorithm for the synthesis of a complete train traffic at a station equipped with electrical set of safety functions is developed on the basis of interlocking system (EC) - regardless of the LTO and digital models of SSP and TD. technical implementation (relay, relay- processor, microprocessor) ____________________________ These conditions were first formulated Synthesis of safety functions for railway automation in [6] for all technological operations with and telemechanics systems, Dec. 11, St. Petersburg, Russia. routes (Table 1). The list of implementation EMAIL: vasilenko.p.al@gmail.com (P. A. Vasilenko); given in [4, 5] will be called the basic set of 9416579@gmail.com (M. N. Vasilenko);hva1104@mail.ru safety functions (BSSF). (V.A. Hodakovskij) Because of traffic safety violations, a ©️ 2020 Copyright for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0). threat to life and health of people is created, CEUR Workshop Proceedings (CEUR-WS.org) significant material damage is inflicted on the state, cargo is lost, expensive equipment is put out of action. 160 Table 1 Basic set of security functions № Security features 1 control of the end position of the running switches; 2 control of the correct position of the guard switches; 3 control of lack of transfer of switches to local control; 4 checking the absence of closure switches in other routes; 5 control of the free running sections; 6 control of the freedom of oversized sections; 7 checking for no cancellation of routes; 8 checking the absence of artificial cutting; 9 checking the actual closure of sections in a given route; 10 checking the opening of sections when canceling the route according to the specified algorithm; 11 checking the opening of sections during artificial cutting according to a given algorithm; 12 protection of closed sections from premature opening when applying and removing a shunt on the rail circuit; 13 protection of closed sections from premature opening when switching power feeders; 14 protection of closed sections against premature opening in case of loss of a shunt for a specified time; 15 control of the freedom of the receiving and dispatching track; front contact of path relay П; 16 control of the absence of assignment of hostile (frontal) routes in the opposite throat of the station before assigning a route to this receiving-departure route; 17 verification of the absence of transfer of the receiving-departure track to the local control in the opposite throat; 18 checking the absence of inclusion of the fence of the receiving and dispatching track; 19 checking the actual exclusion of frontal routes for a given receiving and departure route after setting the route; 20 control of the freeness of the first block removal section during auto-blocking; 21 control of the presence of the wand key in the control apparatus; 22 control of the correctly set direction of movement with two-way auto-blocking; 23 checking the actual closure of the direction change circuit with two-way auto-blocking; 24 control of the freedom of the haul with semi-automatic blocking; 25 control of compliance of the signal indication of the traffic light with the Instruction for signaling on the railways of the Russian Federation; 26 control of the absence of inclusion of an invitation signal indication at a traffic light; 27 control of the closed state of hostile traffic lights; 28 checking the closed state of obstruction traffic lights (control of the absence of activation of the obstruction alarm at the crossing); 29 checking the inclusion of permissive signal indications at a traffic light with a time delay sufficient to close the movement at the crossing; BSSF is mandatory for most stations In [1,2], the LTO alphabet and its equipped with EC on any element base. This set is correspondence to the SSP elements are defined, minimal and describes only the basic safety and in [3], a description of LTO in XML is defined. functions of the station systems of the railway. In The safety functions in Table 1 can be compared the event that the station is equipped with with respect to the letters LTO (elements of the additional RAT devices (for example, a rolling SSP), such a correspondence is given in Table 2. stock derailment control device, control and gauge devices, and others), the BSSF should be supplemented with appropriate safety functions. 161 Table 2 Compliance of security functions with the letters of LTO Element of SSP Element of LTO Number of SF (from table 1) Switch S 1,2,3,4 Traffic lights F 25,26,27 Block joint C 5, 6, 7, 8, 9, 10, 11, 12, 13, Path section L 14 Crossing P 28,29 Since the BSSF (Table 1) contains a description of is a subspecies of the track section), Table 2 can be the specific elements of the SSP (for example, the specified using the non-terminal LTO dictionary. receiving-departure track in LTO (Table 3). Table 3 Correspondence between SF and LTO using a nonterminal dictionary. Element of SSP Element of LTO Number of SF (from table 1) Traffic lights F {25, 26, 27} Crossing P {28, 29} Centralized switches S {1, 2, 3, 4} Switch and non-switch section of the L,C {5, 6, 7, 8, 9, 10, 11, 12, 13, path 14} Receiving and sending way {15, 16, 17, 18, 19} Area of approach and removal {20, 21, 22, 23, 24} Table 4 shows the correspondence of the attributes and security functions. LTO letters to the XML Table 4 Correspondence of SSP elements to the letters of LTO, XML and SF attributes Element of SSP Element of Attribute XML Number of SF LTO (from table 1) < Path section Id = “”(identifier) X = “”(coordinate x) Switch and non-switch Y = “”(coordinate y) {5, 6, 7, 8, 9, 10, section of the path L,C Appointment = “” 11, 12, 13, 14} Specialization = “” NonstopPass =“” … High-speed movement =“”/> {15, 16, 17, 18, 19} way receiving and dispatching” Specialization = “” Nonstop Pass =“” … High-speed movement =“”/> {20, 21, 22, 23, 24} removal” Specialization = “” Nonstop Pass =“” … High-speed movement =“”/> The movement of trains at stations of trains, four types of routes are distinguished equipped with EC systems is routed and, therefore, (proposals of LTO): departure , reception, transfer, all routes have a clear set of properties, which shunting. The implementation of the LTO include: Route type, technological operations with proposals corresponding to certain routes in the TD the route, route components. During the movement 163 3. Algorithm for the synthesis of a formation module and the description of the parameters in XML is given in [3]. complete set of safety functions. words (elements of the SSP) for all LTO proposals Using the digital model of TD and SSP in (TD routes). The FSSF synthesis algorithm is the IFTD format, it is possible to form a complete shown in Figure 2. FSSF is recorded as a table of set of security functions (FSSF). To do this, it is safety functions (TD) for all routes. necessary to write down the SF of all letters and Start List of SF for elements of Element of SSP Initial data BSSF the SSP (Letters LTO) List of all routes according Departure routes Transmission routes to dependency table Receiving routes Shunting routes Are the SF of all The next route routes recorded in the no (proposal of LTO) is FSSF? selected from the list yes Selected sections of the SF offers are recorded route (words of the no in FSSF? LTO sentence) FSSF full yes LTO word list from sentence The end For the next section, SF of all words are elements of the SSP no written in are selected (letters FSSF? from the word LTO) yes List of letters LTO from word SF of all letters are yes recorded in FSSF? no The next letter LTO is selected from the list The letter corresponds to the SF from the BSSF The letter and SF are recorded in the FSSF Figure 1: Algorithm for the formation of FSSF 164 4. Conclusions It is shown that the expansion of the basic The concept of a basic set of safety set into a full set of safety functions for a particular functions for EC systems is introduced, which can plant can be achieved on the basis of a formal be supplemented with the development and synthesis algorithm using technical documentation modernization of systems. for the RAT systems. References 4. Works on the theory of synthesis and diagnosis 1. Vasilenko M.N., Vasilenko P.A., Telezhenko of finite automata and relay devices / Ed. T.A Principles of construction and application of V.V.Sapozhnikova, Vl. V. Sapozhnikov - SPB: the language for describing track objects of railway "ELMOR", 2009 - 900 p. automation and telemechanics // Automation, 5. Microprocessor centralization systems: communication, informatics. 2020. No. 5. S. 23- textbook. for technical schools and colleges of 29. railway transport / Vl. V. Sapozhnikov, V. A. 2. Vasilenko M. N., Vasilenko P. A., Telezhenko Kononov, S. A. Kurenkov and others; ed. Vl. V. T. A. Principles of construction and application of Sapozhnikov. - M .: UMTs ZhDT, 2008, - 398 p. the language for describing track objects of railway 6. Basics of designing electrical interlocking of automation and telemechanics // Automation, intermediate stations / Kononov V.A., Lykov A.A., communication, informatics. 2020. No. 7. P. 15- Nikitin A.B. - Ed. Route 2003, -315s. 21. 7. Vasilenko MN, Bubnov VP, Bulavskiy PE, 3. Vasilenko M.N, Vasilenko P. A., Bulavsky P. E. Vasilenko PA Errors in technical documentation of Software implementation of the language of track railway automation and telemechanics and their objects in the automated workstation for impact on the safety of train traffic. Automation in maintaining technical documentation // transport. 2019. No. 1. Volume 5.S. 94-112. Automation, communication, informatics. 2020. No. 8. S. 29-33. 165