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.
Security features control of the end position of the running switches; control of the correct position of the guard switches; control of lack of transfer of switches to local control; checking the absence of closure switches in other routes; control of the free running sections; control of the freedom of oversized sections; checking for no cancellation of routes; checking the absence of artificial cutting; checking the actual closure of sections in a given route; checking the opening of sections when canceling the route according to the specified algorithm; checking the opening of sections during artificial cutting according to a given algorithm; protection of closed sections from premature opening when applying and removing a shunt on the rail circuit; protection of closed sections from premature opening when switching power feeders; protection of closed sections against premature opening in case of loss of a shunt for a specified time; control of the freedom of the receiving and dispatching track; front contact of path relay П; 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; verification of the absence of transfer of the receiving-departure track to the local control in the opposite throat; checking the absence of inclusion of the fence of the receiving and dispatching track; checking the actual exclusion of frontal routes for a given receiving and departure route after setting the route; control of the freeness of the first block removal section during auto-blocking; control of the presence of the wand key in the control apparatus; control of the correctly set direction of movement with two-way auto-blocking; checking the actual closure of the direction change circuit with two-way auto-blocking; control of the freedom of the haul with semi-automatic blocking; control of compliance of the signal indication of the traffic light with the Instruction for signaling on the railways of the Russian Federation; control of the absence of inclusion of an invitation signal indication at a traffic light; control of the closed state of hostile traffic lights; checking the closed state of obstruction traffic lights (control of the absence of activation of the obstruction alarm at the crossing); 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 equipped with EC on any element base. This set is minimal and describes only the basic safety functions of the station systems of the railway. In the event that the station is equipped with additional RAT devices (for example, a rolling stock derailment control device, control and gauge devices, and others), the BSSF should be supplemented with appropriate safety functions.
In [
The safety functions in Table 1 can be compared with respect to the letters LTO (elements of the SSP), such a correspondence is given in Table 2. 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).
Crossing
Centralized switches Switch and non-switch section of the path
Receiving and sending way Area of approach and removal
Table 4 shows the correspondence of the LTO letters to the XML attributes and security functions.
Category = “” Length = “”
… LatencyACS = “”/>
<Switch
Id = “”(identifier) X = “”(coordinate x) Y = “”(coordinate y)
SwitchType = “”
RailType = “” BrandCrosspieces= “”
… RadiusCurve =“”/>
< Path section
Id = “”(identifier) X = “”(coordinate x) Y = “”(coordinate y)
Appointment = “” Specialization = “” NonstopPass =“”
… High-speed movement =“”/>
<Path section
Id = “”(identifier) X = “”(coordinate x) Y = “”(coordinate y)
Specialization = “ receiving and dispatching”
Specialization = “” Nonstop Pass =“”
… High-speed movement =“”/>
<Path section
Id = “”(identifier) X = “”(coordinate x)
Y = “”(coordinate y) Specialization = “approximation
removal” Specialization = “” Nonstop Pass =“”
… High-speed movement =“”/>
{1, 2, 3, 4} {5, 6, 7, 8, 9, 10, 11, 12, 13, 14} {15, 16, 17, 18, 19} {20, 21, 22, 23, 24}
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
Element of SSP List of all routes according to dependency table
yes FSSF full
The end
Are the SF of all routes recorded in the
FSSF? no
The next route (proposal of LTO) is selected from the list
Start Initial data Departure routes
Transmission routes Receiving routes
Shunting routes SF offers are recorded in FSSF?
no yes
Selected sections of the route (words of the
LTO sentence) LTO word list from
sentence SF of all words are written in FSSF? yes no 3. Algorithm for the synthesis of a formation module and the description of the complete set of safety functions. parameters in XML is given in [3]. 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 BSSF
List of SF for elements of the SSP (Letters LTO) For the next section, elements of the SSP are selected (letters from the word LTO) List of letters LTO from
word yes SreFcoorfdaeldllienttFeSrsSaFr?e
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 4. Conclusions
The concept of a basic set of safety functions for EC systems is introduced, which can be supplemented with the development and modernization of systems.
It is shown that the expansion of the basic set into a full set of safety functions for a particular plant can be achieved on the basis of a formal synthesis algorithm using technical documentation for the RAT systems.