Interlocking logic is a term used for various logical relationships provided between physical entities in a railway station yard such as points, signals, track circuits etc. The present invention relates to a Railway yard control system with Generic Interlocking incorporates a proven logic to maintain interlocking relationship through a microprocessor or a micro-controller based system thus ensuring safe train movement. This method also ensures easy verification and validation of the interlocking logic as it incorporates generalized interlocking logic equations, which are suitable for any station and is designed to be independent of any hardware or software environment. These generalized equations in reference with station yard data formulate specific equations for any particular station, which perform interlocking. Interlocking of various signal routes in a railway station yard is a must for safe train movement.
The different systems in vogue today are:
Mechanical Lever Frame System:
Interlocking systems started with mechanical lever frames to select safe route for train movement. All the mechanical levers are interlocked in such a way that the selected route is set for safe movement of the train, by preventing operation of other levers, which can select a conflicting route. Increase in the size of lever frames with increased size of yards made the system unwieldy. This increase in lever frame size not only requires large space but also increases maintenance requirements.
Relay Interlocking (RI) Systems:
The next generation interlocking systems consists of electro-magnetic relays. The lever frames are replaced with electro-magnetic relays to provide relay based interlocking systems. This method substantially reduces the space requirement and increases the operational facility/ease. Relay interlocking increases the speed of operation. These interlocking systems use a large number of relays and need complex wiring to be done between panel, relays and outdoor cables connecting to field equipment 'ike signals, points machines

etc. The maintenance of these systems needs human checking of individual relays, extensive wiring and thousands of spidered joints.
The interlocking diagrams are very complex in terms of entities represented in each diagram and the volume of wiring information it holds. This naturally increases human fatigue and reduces the reliability of maintenance. Another disadvantage with this method is that, addition of every new function in the station yard calls for lot of changes to be made in the interlocking logic and the systems in use, involving substantial human effort, that may even lead to possible traffic detentions.
The disadvantages with Route Relay and Panel Interlocking systems in brief are as follows:
Interlocking logic is realized in practice, through large-scale use of wiring between the control points and the individual field elements. This can run into many miles of wire length, even for stations with few roads. Addition of a new element into the yard, would call for substantial change in the wiring schema, implementation and testing, as also the maintenance of such large lengths of cable.
Cost of replication, even of newer stations, which are same/ similar to an already implemented function is as high as an existing system. There is no distinct advantage gained over replication (as most of the work is hardware driven).
Absence of self-monitoring / health check features
There is no logical grouping of yard elements, which is a necessity in narrowing the scope of troubleshooting, incase of fault occurrence. By design, each railway yard calls for equal or more effort even after implementing similar yards.
The Railway yard control system with Generic Interlocking under our invention is essentially a Microprocessor / Micro-controller based system that

incorporates the interlocking logic into system software and then takes decisions on legitimate yard operations depending on the related functional status at that time, along with the user input. This is a state of the art control system and is versatile in nature, capable of realizing interlocking logic in any Electronic Interlocking System for Railway Signaling by using software modules such as Generic data structures, generic Boolean equations, yard data generator and panel button master to ensure fail-safe interlocking functions for safe train movement.
Acoording to our invention the Railway yard control system with Generic Interlocking, comprising of an interlocking logic capable of realizing software modules selected from Generic data structures, generic Boolean equations, yard data generator and panel button master, wherein the said system is having a built in fail safe functions ensuring safe train movement
The embodiment of our invention viz Distributed railway yard control system is shown in FIG 1 - A block diagram indicating various modules in a typical EI System, and in Fig 2 -A process chart for producing the yard specific data and logic.
The EI system comprises of following modules, as shown in the FIG 1.0.
l.A panel processor, PP that contains input data processing hardware modules, and software logic for validation of the external inputs to the system.
2. A central interlocking unit, CIU containing software for voting on the inputs, hardware for health monitoring, vital communication software/hardware.
3. Object controllers, OC containing hardware modules for data gathering, storing and communicating to the central interlocking unit.
4. An internal & external data logger, IDL and EDL with hardware and software modules to store every occurrence of an external and internal events.
5. A maintainer's terminal, MT as a computer, containing software
applications to store permanently all event occurrences for the purpose of
system troubleshooting.

The detailed operational cycle of the "Railway yard control system with Generic Interlocking as realized in our invention is as under:
Button inputs through an operator panel are first received and validated by the panel processor for correctness and completeness. After successfully validating the input against pre-defined static valid operations set, the data is passed on to the Central Interlocking Unit. The CIU then executes the interlocking logic with the help of data gathered from the object controllers; along with valid data set received from PP. This cycle happens for every user input.
The results of the evaluation of interlocking logic in every cycle are passed on to respective OCs to communicate with the field elements of the given yard. Every status change in the yard, user operations is continuously recorded in IDL, MT and the external data logger.
Central Interlocking Unit (CIU)
The CIU is a combination of fail-safe hardware elements, operational intelligence in the form of software, also referred to as interlocking logic software and a complete set of hardware and software elements to connect to object controllers, panel processors, maintainers terminal, internal and external data loggers.
The software in the CIU consists of health monitoring, input, output validation, intelligence pertaining to selection of the equations to be executed, and software modules to guide the system through to a fail-safe operation. The interlocking software modules that consists of intelligent operational logic software, data structures as required for the programming language on the given hardware, data files that are used as input elements in the process of equation generation. The process of conversion is depicted in the FIG 2.0.
The interlocking software encompasses variation in the yard types such as single line, double line; yard element types such as single ended and double-ended points. Types of signals main signals (automatic and semiautomatic),

shunt signals and various other control elements such crank handles and Level crossings. The system is also made to address the different practices in vogue such as British and Siemens methods.
Generic Interlocking Logic is a functional module, of EIS, and is responsible for implementing the yard specific controls. This module is designed considering wide range of possible yard variations. Components of the "Generic Interlocking Logic"
♦ User Defined Selection Table
♦ Look up table representing the local practices
♦ Generic Boolean Equations - representing relay logic
♦ Generic Data Structures
♦ Specific Data structures
♦ Specific Boolean equations
User Defined Selection Table:
Selection table is a format in which the topology of the railway yard and the interconnection between the yard elements is listed on paper. The Selection table is listed in route wise, point wise and slot wise Tables.
Look up table representing the local practices:
This is an equivalent of a data structure that encompasses the typical variations in a given railway yard and overrides the normal interlocking principles.
Generic Boolean Equations:
Generic Boolean equations are a set of rules that govern a functional module in a typical railway yard such as route setting, signal clearance, route cancellation etc. These Boolean equations generally represent all typical yards.

Generic data Structures:
Generic data structures are a digitized format of the user defined selection table. The Data Structure consists of the yard specific data listed in the selection table. The Generic data structures are also given in three formats as follows:
♦> Route wise data structure
♦ Point wise data structure
♦> Slot wise data structures for Crank Handles, Level Crossing and Ground Frames
Specific Data structures & Specific Boolean equations are instances of code / data generated for each station yard that resides separately in any given hardware. Each row in the input selection table is converted into a data structure represented as yard element wise.

Relay Logic
The interlocking logic that controls the station yard is a realization of commonly referred relay logic. The relay logic is a combination of the number of relays required to represent the physical yard completely and method of monitoring and logging the status on real time basis. The relays are electro mechanical entities that represent the status and change of an individual yard element or part of it. The schema implemented in the EIS uses the relays listed in the following table referred to as TABLE 1.0
Relay Variables of "Railway yard control system with Generic Interlocking".
This table below gives the detailed nomenclature, functionality and purpose of different relays in relay interlocking systems and their equivalent interlocking software logic in the form of internal variable outputs.

The above one is a Relay table used in the "Railway yard control system with Generic Interlocking
An operational sequence leading to generation of program intelligence for a specific yard is given as under
The user selection table (fig 2 Item A) that represents the signaling plan for a given yard is converted to a digital format also referred to as Generic data structures. (Fig 2 Item B). The different data structures created are: Point, route and slot each.
A software tool also assigns a unique numbering scheme to individual yard elements in the process of creating the digital format mentioned in point 1 above.
The generic Boolean equation (fig 2 Item E) uses the data structures in the point 2 above and creates a station specific operational intelligence software unit, (fig 2 Item D)
The central interlocking Unit hardware together with the Specific equations above forms the core component for any station that can then be connected to other operational equipment

We Claim.
1. Railway yard control system with Generic Interlocking, comprising of an interlocking logic capable of realizing software modules selected from Generic data structures, generic Boolean equations, yard data generator and panel button master, wherein the said system is having a built in fail safe functions ensuring safe train movement.
2. Railway yard control system with Generic Interlocking as claimed in Claim 1 the software modules along with the Relay list such as herein described as an input, capable of implementing interlocking logic for a specific station, that contain tables representing the data structures, yard data represented as header files, equations pertaining to the station for which the system is implemented.
3. Railway yard control system with Generic Interlocking as claimed in Claim 1, capable of converting the static yard data into data files in the form that can be used by the interlocking software.
4. Railway yard control system with Generic Interlocking as claimed in Claim 1, wherein a provision exists for executing a sequence of operations ensuring fail-safe output generation.
5. Railway yard control system with Generic Interlocking as claimed in Claim 1, is capable of converting of the station specific yard data into binary files using a custom-built means.
6. Railway yard control system with Generic Interlocking as claimed in Claim 1 is capable of leading to operational decisions, in the CIU, even with the degraded behavior of the connected hardware components.
7. Railway yard control system with Generic Interlocking as claimed in Claim 1, is provided with a means for implementing a process that automatically validates the correctness of the yard data, entered and represented in a form that is internal to the system.
W 4

8. Railway yard control system with Generic Interlocking as claimed in Claim
1, is capable of working with independent and separate functional modules,
representing the logic implementation and the internal representation of the
yard data elements.
9. Railway yard control system with Generic Interlocking according to any of
the claims from 1 to 9, substantially as herein described with reference to the
accompanying drawings of figl and fig.2